[Music] Women are turning up dead in their offices in suburban Texas. Bodies are found only a few miles apart. Investigators must link the crimes together in the hopes of stopping a killer before he strikes again. A convenience store owner is stabbed to death in broad daylight. [Music] Although the crime scene yields few leads, the victim's bones reveal the signature of the killer. Scientists must piece together small clues to solve the crimes. Often, criminals are careful to leave no evidence behind, but the methods of the murder itself can create a lasting impression. Especially when the tools of a trade leave an innocent victim marked for death. [Music] [Music] Houston, Texas, one of the fastest growing metropolitan areas in the United States, boasts economic growth and rapid expansion. It's a mecca for people seeking a better life and greater opportunities. But in 1996, Houston's suburban workforce found themselves terrorized at the hands of a sadistic killer. At approximately 5:30 p.m. on January 5th, Jerry Cowan returned to the storage rental facility he owned with his wife Rita in Spring, Texas. Cowen was surprised to find the door to Rita's office locked and the closed sign posted on the door. Rita, Rita. Panicked, Jerry smashed the window. Rita, Rita. The office appeared ransacked. But what Jerry saw next was devastating. He notified police. Hold off for the sheriff's department, please. Quick, quick. A nearby patrolman arrived within minutes. She's choking. She's been found. Okay, she's been found. She's in here. But it was still too late. There she is. All right, sir. I need you to stay in here. Okay, just stay in here. Let me see. Rita Cowan was dead on arrival. 4833, we have a confirmed DOA. We need a supervisor. Crime scene investigators were called to the residence. It appeared she was strangled with a self-locking plastic tie wrap. Rita's hands and feet were bound and investigators speculated she worked one hand free in a desperate attempt to stay alive. Harris County Detective Ben Bell investigated. He was saying something about the money box. It was a very brutal way to die. the tie wrap around the neck. The uh our victim would have known that she was dying. There wasn't any way to get the tie wrap off of her neck. The motive appears to be robbery. Uh we believe it was premeditated because the murder weapon, the tie wraps were brought to the scene from outside the scene. The zip tie wraps were an industrial gauge plastic box over the county. Investigators searched the apartment and office for clues to the killer's identity. We got a contract. Although money was stolen from the cash box, it was something else that caught Detective Bell's eye. Got cash box money. What's this over here? It's a contract. A partially filled out rental form. 308 out here. Laying on the desk was a contract uh that was used by the many storage warehouse people and all of the company information was filled out and the storage unit number was written on it, but there wasn't any uh customer information on the contract. Detectives began their investigation looking to those closest to the victim, hoping for answers. With any type of homicide, you you start basically at home, move out from the home, the family. Detective Bell interviewed the victim's husband, Jerry Cowan. Get a little bit get a little bit big information from here. What What time did you get home this afternoon? About 5:15. And where were you coming from? Just based on the circumstances that he was one of the last people to see her alive. I talked to him extensively. Obtained a statement from him. Cowen told the detective he saw his wife Rita alive that morning as he was leaving for work around 8 a.m. today. Um, no. I think I'll wait till they talked about running some errands and everything seemed fine. Yeah, I'm kidding. I got three more days, actually. All right. When Cowan returned from work around 5:30, he found his wife dead and he was able to pretty well aliy himself for the entire day he was at work. At the autopsy, the medical examiner noted deep abrasions to the victim's neck. The ligature around her neck was drawn with extreme force. She didn't have a chance to survive. The official cause of death was listed as strangulation. Additional contusions were found on the victim's bound wrists and ankles. The plastic tie wraps provided the killer with a weapon that combined efficiency and deadly force. The tie wraps were sent to the Harris County Crime Lab for analysis. Matthew Clemens is a toolmark examiner at the lab. In tool mark identification, uh you have to be able to uh recognize a pattern across a three-dimensional item that that that it's going to have shape to it as opposed to a flat um you know, a flat piece of paper or something like that. So you have to kind of have to train your eye and train your mind to to look at these things across three dimensions. The tie wraps were industrial grade, common to the electrical and air conditioning trades. At first they appeared to be generic with no distinguishing features. But under magnification, Clemens noticed something. The ends of the cable ties had been cut. There were tool marks present. This was a key discovery because tools, in this case, a pair of pliers or wire cutters, leave distinctive marks and the ties were cut to equal lengths. The wire cutters have a blade and that blade actually presses into this the the plastic strap. The surface variations of the blade are going to scratch basically a set of lines on that cut surface. These are the striations that we use for comparison. Much like a fingerprints identified to an individual, you're identifying that set of markings to an individual tool. Investigators believed if they found the tool that cut the tie wraps, they also might find the killer. It can break a case. It can be your one. It could be the lynch pin of your of your case if you don't have any fingerprints or you don't have any DNA. If you don't have any other evidence actually linking your suspect to your scene, if there are tool marks left behind, that's as good of an identification if that tool was recovered from his possession. Crime lab technicians also analyzed the rental agreement found at the crime scene for possible fingerprints undetectable to the naked eye. Latent print examiner Gail Mills. When the document was discovered to be partially filled out, uh we knew that it had been handled on a porous item such as this paper. When a person touches the the paper, the residue from the fingerprints is then transferred to the document or the paper. And within this residue is things like fats and oils and salts and amino acids. Mills applied a chemical called DFO to process the paper. The DFO reacts to the amino acids in the residue of the fingerprint. The paper is then dried and the latent print is studied using an alternate light source. A light source is an intense forensic light that we use uh to view certain types of evidence. There's varying wavelengths within the light source that you can change to to cause different types of evidence to flues. Um the document is examined under those light sources and if the latent print is there that has reacted with the amino acids, it should flues. Deputy Mills had isolated one fingerprint that did not match the victims. [Music] Uh, at that point, the fingerprint needs to be uh, photographed in order to preserve it. So, that's what I did in this case. [Music] It was now up to investigators to link the unidentified print to a suspect. [Music] At the Harris County Sheriff's Office, Detective Bell reviewed the evidence. Although he knew the plastic zip ties were cleanly cut and the killer left behind a fingerprint, neither clue brought him any closer to a suspect. Detective Bell went back to Rita's husband, Jerry Cowan, and asked him to check his residence to see if any additional items in the cash box were missing. Cowins scoured the apartment and discovered some jewelry and two money orders were also missing. Investigators looked to trace the money orders. Jerry recalled that about two or three days prior to the murder, uh, he and his wife had purchased two money orders from the grocery store close to their residence. They used the money orders to pay their bills. One money order was for several hundred was used to pay the car payment, and then there was a second money order for $10. Jerry Cowins said he knew the money orders were stolen because the carbon receipts were missing. They were blank. Since the money orders were as good as cash, Detective Bell believed the killer may have been motivated by money. He set out to track down the money orders. I'm going to go ahead and show you pictures. Harris County detective showed the clerk a picture of Rita Cowan. Yeah, she might have come in Monday or Tuesday last week. The clerk remembered Rita purchasing the money orders. Yeah, but there was a problem. probably one day. The store didn't keep records of the money orders. No, I have investigators moved quickly and contacted the company that issued them. So, we'd have to call the company itself to verify. If you call the company and you have give them that number, they can trace it. Hey, this is Detective Bell with Sheriff in Houston. I'm trying to trace a couple of money orders. I contacted the money order company and advised them that we're working a homicide. The money order company told me that they could track the money orders for us, but that it would take them several weeks before they could get back with us. Detectives know if they don't have a suspect within 48 hours, their chances of ever solving the crime drop dramatically. Any delay in a homicide investigation would keep the killer on the streets longer. And as detectives quickly learned, the delay would also prove to be deadly. Detectives were struggling to solve the vicious murder of Rita Cowan, but their killer seemed to be one step ahead of them. In neighboring Montgomery County, just 17 days after Rita Cowan was killed, another woman was found strangled in her office. The victim was real estate agent Janice Vogle. Her hands and feet had been bound with red electrical wiring, and around her neck was a thick plastic tie wrap, just like the one used to strangle Rita Cowan. News of Janice Vogel's murder quickly spread throughout the Houston metro area and people were frightened. Ben, hey, uh, just watching the news and, uh, Montgomery County is working on a deal. Uh, a detective in the Harris County Sheriff's Office saw the story and quickly recognized similarities to the Rita Cowan murder, apparently strangled. Uh, I jotted down some notes and everything like that. Maybe you can give them a call and see what they're up to. Detective Bell contacted investigators in Montgomery County. All right. Anything else? Let me It was likely they were looking for the same killer and likely he would strike again. It appeared that the uh same type of tie wraps had been used in that murder. Also, prior to Miss Van Hus being murdered, we had not had any cases even remotely similar to that. And then for a second homicide to occur uh 10 days later in close proximity uh we felt that we had a predator out there and that he was probably going to continue to murder victims until we caught him. A fax came in from Republic money orders. Investigators knew they had a major break. They had discovered that the larger money order had been cashed and they had sent me a photocopy of the money cashed money order front and back showing uh a purchaser's name and the back had been endorsed by another person. The $400 money order had been cashed at Ice House, a local bar, and the signature was revealing. The front of the money order showed that the money order had been purchased by a Roy Landry uh who with an address in South Houston. There was a second signature on the back of the money order, but only the first name Bill was legible. Back of it there. We conducted a computer check on Mr. Landry located a rather extensive criminal history on him and uh immediately determined that he was a potential suspect in our case based on his his past criminal history. Detective Bell finally had a suspect. Now he needed to find him. We located a mugsh shot photo of Roy Landry, placed it in a photo spread, and my partner and I drove out there to the ice house. Wine, if you can believe that. If this is all you got, I'm going to The ice house was a no frrills beer and whiskey hangout where patrons minded their own business. Investigators went there in the hopes of finding more information about the money order. Harris County Sheriff's Office. They presented the photo lineup with Roy Landre's picture. You sure you don't recognize him? The owners didn't recognize anyone and they had never heard of Roy Landry. Positive. Okay. How about the back? Detectives showed them the other signature with the first name Bill. Bill Kutner. This they recognized right away. It was Bill Kutzner. They had another check from Kudner, one that bounced. The signatures were nearly identical. They immediately recognized the name as Bill Kutzner and and he's the person that is their refrigeration and air conditioning man out there. Bill left us something bad. Detectives needed to speak with both Kutzner and Landry. So he they reached Roy Landry first. We were able to make contact with Mr. Landry. Uh he came down here to the homicide division to provide us with some limited information uh regarding Mr. Kutzner and where we might be able to locate him. For the purchaser is Roy Landry. They discovered he had a lengthy criminal record and when they caught up to Landry, he was reluctant to give them any information. You can either be a witness or you can be a defendant. What's it going to be? All right. I'm not going to take the rap. Landry gave in to detectives and gave up information on Cutner's whereabouts about doing a robbery or something. Yeah, he said something about doing a robbery. Said it was an easy pick cuz lady was by herself. I asked him why he didn't need to do it himself and he said he lived too close. You know where that stuff is now? Yeah, it's at that house. Investigators drove to Bill Cutzner's house. Most of the windows didn't have curtains on them. Uh there seemed to be very little furniture in the house, and it almost appeared that the house had been abandoned. Kudzner was nowhere to be found. But then, Detective Bell made a startling discovery. When I was walking back to our car, uh, I stopped right and noticed right laying in the driveway, almost embedded in the in the gravel, was one of the large white tie wraps that had been used in both of the homicides. Detective Bell knew the tie wrap was circumstantial evidence, insufficient to make an arrest. Each clue brought them closer to catching the killer, but detectives needed to hurry if they were to stop him before he struck a third time. Yep. Investigators were closing in on the killer who was terrorizing a community. Two women were dead and detectives were working round the clock to catch him before he killed again. Detective Ben Bell did a background check on their prime suspect. His full name was Richard William Cutsner and he had a history of arrests. None of the neighbors. Detective Bell interviewed Kutzner's ex-wife. There's been hardly any communication at all. She said she hadn't spoken with him in weeks and she had no idea where he might be. But then she recalled a key incident truck was and they took that and that was really the last of anything we had left. Cutner had fallen behind in the payments on his truck. Why do you want man? I'm coming. And a few weeks earlier a repo man showed up to take possession of it man. I don't have nothing to do. Kutzner was furious, but there was nothing he could do as he watched his truck being taken. His ex-wife remembered he didn't even have a chance to remove his gear from the back of the truck. He was very violent. She recalled the name of the auto company that took possession of the vehicle. Drunk. I can smell alcohol on him. You know, that's an old story. That's never going to change. It was A&W Motors if I'm not mistaken. Investigators went to the car lot and spoke with the manager. He remembered Cutsner's red truck coming in. [Music] He had told us that when he re the truck was repossessed, all of Kutzner's personal papers, uh, air conditioning equipment, tools, all of his belongings were still in the truck. That Cutner had contacted him, said that he was going to come by and pick the stuff up. And then when he never showed up, they removed all of Cutner's belongings from the truck, boxed them up, and locked them in one of their sheds for safekeeping. Investigators looked at Kutzner's possessions, careful not to touch anything. Wanting a closer look, they chose to obtain a warrant. We could see that several of the ties similar to what had been used in our case and the McGomery County case were clearly visible in the box. Since we were dealing with the possibility of two capital murder cases here, we decided to air on the side of caution and went ahead and obtained a search warrant before we went through the box and all of Kutzner's belongings. a little better. A few hours later, investigators returned with a warrant. They discovered a mound of evidence. Yeah. Once we got the box, we found that there were tie wraps that matched the Harris County case. There were tie wraps that matched the McGomery County case along with red wire. They also found a $10 money order. as well as a tenant information form on unit 308. It matched the contract found on Cowen's desk. Parental information form with the unit number on it. Investigators also retrieved a pair of diagonal wire cutters. Examiners at the crime lab had already established the killer had used a cutting tool, such as wire cutters, at the crime scenes. [Applause] Forensic examiners compared the red wire from the suspect's belongings to the wire used to bind Janice Vogle's feet. Ultimately, what you want to try to find in the end is the same pattern of striations on your evidence item that you made on your known items. A high-owered magnifying glass would be used to enhance the wire patterns. And if you have a sufficient quantity of these striations, then I can render an opinion that no other tool could have made that mark. Based on all of the evidence that we were able to recover from the used car lot, we were able to obtain an arrest warrant for Bill Cutzner for capital murder for the case in Harris County. Mind if we come in? One time suspect Roy Landry had told investigators where Cutner was staying. Harris County officers decided to close in late at night when Cutzner would likely be at the residence and bystanders would be minimal. Detectives entered the residence and found Bill Cutzner sleeping on the couch. Detective Bell, roll your stuff. Roll your stuff. What are you on? You're under arrest. Another mary orders bail. He was arrested without incident. stand up. And he denied any involvement in the murders. Said you're under arrest. Well, that's all I know about the money orders. What else do you want? With the suspect in custody, investigators continued to strengthen the case against William Richard Kutzner. Latent print examiner Gail Mills compared Kutzner's fingerprints against a single latent print developed at the crime scene. The print was found on the partially executed rental agreement. Uh it was photographed and I then compared it to the prints of Richard Kutzner, the suspect in this case. And um I did identify Richard Kutzner's um thumbrint as being on the document. The fingerprint match verified Cutsner had been in the mini storage office, but it did not prove he had committed the murder. Police believed Cutner's gear from his storage locker would seal their case. Toolmark examiner Matthew Clemens knew the ties had been cut by wire cutters, and now he had the tool to match with the markings. [Music] The process that you would use to to compare wire cutters to evidence recovered from a crime scene would be to make your test cuts in a similar medium that's not going to damage the tool itself. After making the test cuts, Clemens used a comparison microscope to do a sidebyside analysis of scratches or striations found on both the evidence and the test cuts. In the case of Bill Cutzner, examiners found exactly what police hoped, a perfect match. The forensic evidence that we were able to obtain, the fingerprint, the tool marks on the wire and the tie wrap showed that Bill Cutner was the person that committed both of these murders and only Bill Cutsner. And Bill Kutzner got what he deserved when he was sentenced to death. He was executed on August 7th, 2002. [Music] Bill Kutzner purposely avoided high-profile locations to commit his crimes. But for some killers, heavily traveled roadways are no deterrence for murder. Foley, Alabama is a small town of 150,000. The crime rate is low and murder is rare. December 4th, 1997. Boldly in broad daylight, a robbery is taking place along a highway. A customer just finished filling his car with gas. He went inside to pay. Nothing could have prepared him for what he saw next. He called 911. 911. What is your emergency? An ambulance arrived in minutes, but it was too late. [Music] See the complaint to 18. The victim's driver's license was found. She was 43-year-old Nancy Bidd, the owner of the store. [Music] Lieutenant Richard Springsteen of the Foley Police Department responded. It seemed that there was a um struggle and there was uh what appeared to be defensive wounds on the hands of the victim. There was um some some blood stains collected, fingerprints collected, um multiple pictures of the crime scene, um and of course the the body of the victim was taken to the forensic sciences laboratories. Investigators noticed the knives on the sandwich counter appeared to have been handled. They were collected as evidence. The victim was autopsied by Dr. James DS at the Alabama Department of Forensic Science. He analyzed her brutal murder. She had at least 35 different stab and cutting injuries to her face, her chest, her extremities. Nancy struggled to survive. She fought her killer ferociously uh as indicated by the dislocated finger and the multiple defensive injuries. When I look at a knife wound on a body, what I'm trying to do is get a sense of the measurements. Uh how far does a knife go into the body? And there's some room for interpretation. For instance, in a stab wound to the chest, the depth of penetration of a stab wound is different depending on whether or not one is inhaling, expanding their chest, or exhaling. Dr. DS noted the width and depth of each wound as well as cuts left on the victim's bones. DS compared the stab wounds to each of the knives collected at the scene. In NY's autopsy, it was easy to determine that the stab wounds had actually penetrated into the body up to approximately 4 four and a half inches. That actually penetrated through bone, through rib, and through the breast bone. You look at the injuries for the type of weapon that might be used and I measure each and every one of those 35 stab wounds. I measure how long the wound is on the body, how deep it penetrates into the body. That penetration gives you an idea of how long the blade is. And looking at the suspect knives that were brought in for me to compare against the wounds on the body, it was fairly easy to rule those out because the blade lengths weren't right. They weren't the proper thickness or the proper width. So, none of those fit the wounds that were present on her body. I didn't notice anyone inside. Came back out, Maverick was still there. The police located a witness, perhaps the last person besides the killer who saw Nancy Bidd alive. The witness bought gas that morning. just had the he recalled as he returned to his car, he noticed a green Ford Maverick parked at the store. He hadn't seen the driver, but his description of the car gave police their first lead. Although the Maverick has not been manufactured since 1977, a search of motor vehicle records indicated a surprisingly large number of Green Mavericks in the area. [Applause] Police tracked down every Green Maverick registered within a 60-mi radius of the crime scene. Five Adam 628. Correction. Five Adam 6208 Davs, Channel Road 71, north of 64. Drivers were interviewed and their identifications checked. Good afternoon. See license, please. [Music] But after several days, no significant leads were developed. The investigation had stalled. We're looking for a vehicle that matches this description. Obviously, you're not him. Thank you. And although detectives believed the car would lead them to a killer, the trail of green Mavericks had led police to a dead end. 911. What is your emergency? I'm sorry. You said there was a woman down. What's your address there? 10 days after the brutal killing of convenience store owner Nancy Bidd, 911 dispatchers received another distressing call. 911 transfer for a woman down. At the Diamond Gas station, a second woman, Cashier Linda Weber, was found stabbed to death in a back room. The similarities between the crimes were disturbing. The service station was along the same highway as Bidd's gas station. And although the store had a video surveillance camera, the video recorder was torn from the rack, leaving behind no account of the crime. [Music] Examiners lifted fingerprints from the area where the BCR was taken, but results would be inconclusive. For Lieutenant Warren Stewart of the Alabama Department of Investigations, the similarities to Nancy Bidd's murder could not be ignored. Well, both scenes, uh, it appeared to be a robbery and a struggle. We really didn't know what we were dealing with. If we were dealing with just someone needing money or if we had a serial killer possibly within the Foley area. Once again, the victim's body would be examined at the Alabama Department of Forensic Science. As in the first case, Dr. James DS measured Linda Weber's stab wounds and checked for bone lacerations. [Music] In the case of Linda, we didn't have a bone defect to compare to the suspect knife, but we did have the physical measurements of the wounds in the body, which were identical to those in Nancy's body. Dr. DS concluded that both Nancy Bidd and Linda Weber had been stabbed with the same weapon. With a community and local businesses gripped in fear, Bowen County Sheriff's Department formed a task force. It consisted of the county's most seasoned investigators. They structured a plan to catch the killer. Um, this is the area near the Diamond Mart and uh, Diamond Mart's here in the parking lot and this wood line here that's behind the area. The investigators poured over photographs and details from each of the murders. This is the area. They had to act fast to restore peace to the community. Highway 59 is here. Detective Huey Mack of the Bowen County Police Department led the task force investigation. Satellite courthouse. The predominant uh emotion at the time by the public was fear. It is a low crime area. Homicides are rare. But when you have two homicides within just a few days that are believed to have been committed by the same individual, fear was starting to run rampant. With limited evidence, the task force would need the public's help. [Music] They blanketed the local media with information, set up a hotline and requests for tips. It began to pay off. A witness came forward as the police reanvased the area around the second murder scene. Excuse me. Detective Mack believed it might be a solid lead. After the second homicide, we had an individual who described a black male coming from the woodline. Uh within minutes of the crime being reported, our witness uh literally heard the sirens responding uh to the gas station when she saw this individual run from the woodline. She thought she recognized the man from her neighborhood. His name was Calvin Stalworth. Detectives immediately searched the area behind the store. [Music] Amidst the leaves, they found a VCR they believed to be the same as the one taken from the store. [Music] Hoping to find a tape, detectives were disappointed to find the machine empty. The tape had been wrenched from the machine. The woods were dense, but police scoured the large area in search of the tape. They found nothing. We believe the tape not only contained the image of the suspect, but based upon the images that the particular cameras in this store would have captured, more than likely filmed the entire murder. Investigators immediately followed up on the witness's tip. They performed a background check on Stalworth. He had an extensive criminal record and an outstanding warrant. Investigators had a suspect. Now they had to find him. Police distributed his mugsh shot to the media, hoping someone would know his whereabouts. We disseminated to the media uh time and date and location information and asking them to please contact the public if anyone had any information to call a 24-hour number which was set up for this uh so that people could respond. this lady uh took on her own initiative to call and let us know. After seeing his picture on the news, a manager at the city electric company contacted police. But earlier today, about an hour after the murders, the manager remembered seeing the suspect at the electric company. She said the man came in to pay an overdue electric bill. She recalled he pulled out a large roll of money and paid his bill in cash. Hearing police sirens outside, the man grew agitated and nervous. Then he left. What did he look like? Uh maybe that is early. Investigators obtained the billing address from the electric company. family. The address belonged to Stalwart's girlfriend to search for the house. They presented her with a warrant. [Music] As they entered the house, they caught Stalworth in a back room trying to escape. Turn around. Knowing he may be armed and dangerous, the officers drew their weapons and ordered him to surrender. Stop right there. They handcuffed the suspect and began searching the house. All the while, Stalworth professed his innocence. There no weapons in here at all. In the back bedroom, police found incriminating evidence. Detective, I found something. A knife beneath the mattress. This jacket here, is this yours? And blood stained clothing. Standings on the sleeve there. Calvin Stalworth waved his rights and began to talk to the police. He said he had nothing to hide. Stalworth insisted he had nothing to do with the murders and claimed he had never been at the stores. Detectives then told him an eyewitness placed him at one of the crime scenes. If you would explain to me Stalworth quickly changed his story. I got scared and I saw the money lay on the counter and I I needed the money. So Lieutenant Stewart questioned the suspect and couldn't believe what he heard. When he walks in the store and she's laying behind the counter and notices that she's been stabbed. At this point, he says he gets scared and he sees money up on the counter and on the floor. And he said he knew he needed money to pay his bills. So, he just took the opportunity that was presented him. And I just, you know, I saw the cameras and Hello. Hello. Anybody here? The second homicide, he puts himself going into the station. He says as he walks in, he hears a a noise. Ma'am. Ma'am. He looks up and observes a VCR camera in the back room. At this point, he gets scared. He's afraid he's on video and that if he don't take that VCR, he's going to be accused of the homicide. So, he basically goes up, grabs the VCR, and leaves the scene of the second homicide. His his stories were totally unbelievable. Calvin placed himself at the scene of both ladies as they died. Despite his detailed account, detectives were building their own theory of the crimes. How was she laid? And it didn't jive with Calvin. Forensic scientists would bring together all the pieces, confirming that Calvin Stalworth was indeed their man. [Music] Detectives were convinced Kelvin Stalworth murdered two Alabama store workers despite his proclamation of innocence. They knew he was lying. Stalworth's sweatshirt was processed for blood evidence. William Jones of the Alabama Department of Forensic Science explains. We swab the stain to see if we can get a color change for a positive presumptive test for blood. Once we do that, we do further testing to see if there was human DNA present in the stain. [Music] The blood was found to have the same DNA markers as the blood of Linda Weber. But because Stalworth admitted to being at the crime scene, the evidence was inconclusive. Now, Dr. DS would scrutinize the knife found under Stalworth's mattress. Thick single sharp edge. He measured and recorded all its dimensions. The knife was consistent with the size and depth of the wounds to both Nancy Bidd and Linda Weber and the measurements are consistent with those in the wound. Dr. DS then compared the edge of the blade to the cut marks on the bones of both women. This too was a match. I was able to take that knife and measure it, the length of the blade, the width of the blade, the thickness of the blade, and compare that to the piece of bone that I had retained from my original autopsy. And I was able to take the piece of bone and the knife and and literally like a hand would fit into a glove and to show that this knife had the exact same physical dimensions as the wound in the bone. The Alabama State Appeals Court has sent the case back to a Bowwin County Circuit Judge. Although Stalwart's unbelievable story placing himself at the crime scene may have been enough evidence to sway a jury, investigators were quick to point out this case relied heavily on science to ensure a guilty verdict. Without forensics, we probably would not have obtained a conviction in this case. Um, forensic is what linked Calvin Stalworth to both scenes. Once again, science prevailed, bringing Kelvin Stalworth to justice. He was tried and convicted of two counts of capital murder. He was sentenced to death for his crimes. I think I must have left. Most killers try desperately to cover their tracks, but there are times the very act of their violence creates a signature that cannot be erased. Forensic science can reveal that signature and with it a killer who's left his victims marked for death.