woman's life. >> the science was the strongest evidence and was what ultimately convicted her, but it was also what ultimately freed her. early monday morning on october 19, 1992, 23-year-old laura houghteling was seen leaving her bethesda, maryland home, walking to the train station on her way to work. she never arrived. a clue to her disappearance was a peculiar strand of hair found in her hair brush. laura houghteling was an ambitious young woman with a bright future. she had recently graduated from harvard university and had moved

back home with her mother, penny. laura worked for a public relations firm in washington, d.c., and was condemn plating law school. ♪ on the saturday before she disappeared, laura attended the gold cup steeplechase horse races in virginia. when laura didn't show up for work, a co-worker called the house, but there was no answer. laura's mother was out of town on a business trip. next, warren's brother was called. he lived nearby. when he arrived at the house, he found that the back door was unlocked. but there was nothing missing inside. >> as time went on, nobody had heard from laura and this was just totally, totally out of character for her. we checked her bank account, credit cards, checking account. there was nothing there where she had withdrawn money that she would have needed to survive somewhere else.

>> fliers with laura's photograph were distributed at the train station in the hope that someone might have seen her. police also searched the walk in between the train station and laura's home looking for possible clues, but found nothing. when detectives searched laura's bedroom, they noticed a fitted sheet and mattress pad were missing from her bed. laura's mother said that laura always made her bed before leaving for work. four days after laura disappeared, investigators made a grim discovery in the woods near laura's home. at the base of a tree, they found the bloody pillow and pillow case. >> immediately, i recognized the pattern on the pillow case was identical to what i had remembered had been on laura's bed a few days earlier. >> the blood on the pillow case was type a, laura's blood type. a police bloodhound named

sherlock was given some of laura's clothing to establish her scent. when sherlock was released from his cage, he went directly to the tree where police had found the bloody pillowcase. the bloodhound followed the scent through a church parking lot, through a residential area, and straight to the back door of laura's home. >> the dog had a very strong track and actually ran a distance, which indicated to us that he was very definitely on the scent of laura. >> police suspected foul play, but they had no suspects. >> we spoke to everyone that we could that had seen laura or knew laura within the last year or two, and no one could give us any reason for anyone to want to do any harm to her, have any harm to come to her.

>> but police wondered why the bloodhound tracked laura's scent to her back door when she was seen leaving the front door of her home on the morning she disappeared. latte or au lait?

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police suspected foul play in the disappearance of 23-year-old laura houghteling when a bloody pillow from laura's bedroom was found in the woods near her home. to find out whether the blood on the pillow belonged to laura, blood samples were taken from laura's mother, penny, and her brother, warren. using a dna test called restriction fragment link polymorphism, they determined it was the blood from a biological offspring of penny, and that of a biological sibling of laura's brother, warren. the blood on the pillow was that of laura houghteling. next, scientists used another illuminating test on the

mattress to look for blood that may have been cleaned up with water or detergents. luminol is a chemical compound that reacts with the hemoglobin component in blood causing it to glow in the dark. >> it works with very minute traces. once this begins to glow, you can get a pretty good idea of what the pattern of the blood flow was on a particular area. >> after luminol was sprayed on laura's mattress, an invisible blood pattern emerged. >> the left side of the mattress was giving us no response at all. but when we started spraying the right side of the mattress, we were seeing areas of very intense luminescence. and this proceeded from the headboard all the way down to the foot of the mattress. >> next, forensic scientists examined the hair brush found on laura's dresser. they examined over 30 hairs,

presumably laura's hairs. they were all microscopically similar. except one. >> as i was scanning through several of the hairs i recovered from the brush, and all of a sudden one that i looked at, i realized was not a human hair. it was in fact a synthetic fiber. >> the fiber was identified as a strand of artificial hair from a wig. penny told police that her daughter never wore a wig and had never owned one. >> so now that put greater value on this particular piece of evidence. why was a wig fiber in that hair brush sitting on the dresser from her bedroom? >> forensic examiner susan balou also examined bloody pillowcase that was found in the woods. she noticed bloodstains that looked like the impression of a knife, which had been wiped off the pillow case, and another bloodstain on the pillow case was different than the rest.

>> the ridges that i was seeing were different from the weave of the fabric on the pillow case. there were enough that it was consistent with what i was familiar with, with leaving an impression behind. >> it appeared to be some sort of print. but lifting a print from a fabric is difficult. for a closer look, scientists used a protein stain called amido black. next, a wash solution was applied, followed by distilled water. when the print on the pillow case was enhanced by the amido black stain, it was identified as a partial thumbprint. >> we then sat down with the family, it would have been laura's brother and her mother, and explained to her that we felt that possibly laura may have been murdered in the bedroom, based on the amount of blood and based on the circumstances. >> police now had solid evidence

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although police suspected that laura houghteling had been murdered in her bedroom, they were unable to find her body and had no solid leads.

laura's brother warren told police of an incident he had with a part-time gardener he had at hi mother's home. he saw haden clark driving through the neighborhood. when he attempted to speak with clark to ask him if he had seen laura, clark sped away. 40-year-old hadden clark was known to police because of a past arrest for burglary. a few years earlier, clark had also been a suspect in the investigation of a missing young girl, a case that has never been solved. clark was born with brain damage and had difficulty throughout his life. he trained as a chef, but had difficulty keeping jobs. he was currently working as a gardener and other odd jobs. >> he was at one time in the united states navy, and he was discharged and diagnosed as a

paranoid schizophrenic. >> clark was basically homeless, often sleeping in the back of his truck, which he parked in a church parking lot not far from the woods where the bloody pillow had been found. clark got into an argument with penny houghteling just one week before laura disappeared over some tools penny said were missing from her tool shed. the houghtelings also kept a spare house key in the shed. when the police researched clark's financial records, they learned that he had purchased duct tape, braided rope, and nylon cord several days before laura's disappearance and paid for the items with a personal check. investigators were alarmed with what they saw written in the memo section. one word, laura. on the day laura disappeared,

clark purchased a queen-sized sheet from a department store, a size that was too large for the mattress in the back of his truck, but was the same size as laura's mattress. from clark's financial records, police also learned that he rented a storage locker in warwick, rhode island, 450 miles away. an employee at the storage unit told police that clark visited his storage locker two days after laura disappeared. armed with a warrant, police searched clark's storage unit and discovered a secret side of hadden clark's life. >> he had falsies. he had bras, dresses, female shoes. he had female coats. he had wigs. everything that he could wear and look like a female. >> was it possible that the individual seen leaving the

houghteling's home on the morning of laura's disappearance wasn't laura at all, but was, in fact, hadden clark dressed as laura? penny houghteling told police something about laura's attire that they hadn't heard before. >> laura never, ever wore slacks. she was a tall girl. she would wear a skirt or dress. she didn't want to accentuate her height by wearing slacks, so never wore slacks. didn't own a pair of slacks. >> fibers from all of the wigs in clark's storage locker were compared to the wig fiber on laura's hair brush. >> blond was not a possibility since we were dealing with a brown tone as far as the dye goes for this wig fiber. then doing microscopic exam, narrowed it down to one particular wig that was identical in all respects to this particular fiber. >> hadden clark's wig and the

fiber from laura's hair brush from her bedroom were sent to the trace evidence unit at the fbi laboratory in washington, d.c. in their analysis, they used what is called a microspectrophotometer, an instrument that can discern between the 7,000 commercial dyes used in the united states. >> it takes a beam of light and runs it through an object, such as a fiber. and it measures the amount of light that's lost as it passes through that fiber. light is lost at different wavelengths, wavelength relating to color. so a dark brown fiber will absorb more light than a light brown fiber, and it would absorb different colors of light than, say, a light blue fiber. so we simply measure those differences, and then plot that on a chart.

>> dyes are proprietary and trademarked by the manufacturer to prevent duplication. the dye from the wig fiber found in laura's hairbrush were identical from clark hadden's wig. >> they exhibited the exact same color. the fiber is consistent from coming from that wig. they were dyed the same color, the same industry standard, and probably from the same dye lot. >> finally, police turned their attention to the bloody thumbprint found on the pillowcase in the woods. when they compared it to hadden clark's thumbprint, it was a match. police now knew how hadden clark had fooled the neighbor and left the crime scene without creating suspicion. but where had he taken laura's body.

hadden clark was arrested and charged with first degree murder in the death of laura houghteling. although her body had had never been found, prosecutors hoped they had never evidence to convince a jury that laura was, in fact, dead. and that hadden clark was the

murderer. the first-degree murder trial was set to begin on june 14, 1993, but the trial never took place. >> the defendant in the houghteling case just pled guilty. the plea was accepted. the plea was to second-degree murder. >> as part of the plea bargain, clark revealed to prosecutors where he had buried the body. he led them to a shallow grave less than half a mile from laura's home. it had been eight months since laura houghteling's disappearance. >> there was a skeletal part of the body that was sticking out of the ground. the rest of the body was still intact under the ground. >> the autopsy report listed suffocation as a possible cause of death since clark told prosecutors that he had suffocated her. clark also admitted using a knife from the kitchen and a

pair of scissors consisten with the blood found on the discarded pillowcase. >> when you hold a pair of scissors to these marks, they, in fact. fall in line with the outline impression of the marks on the pillow. >> clark didn't reveal his motive for killing laura. police theorize clark was angry over the disagreement he had with laura's mother over the missing tools from the shed. >> looking into hadden's background, we found that any time especially a female would cross him in any way, he would retaliate. it's hard to say exactly why. and i don't know if we'll ever know why. >> clark's confession and evidence gathered by the police told prosecutors all they needed to know about what happened to laura houghteling in the early hours of october 19, 1992.

hadden clark knew penny houghteling was away when he entered the home through the back door sometime after midnight. he picked up a knife from the kitchen and went to laura's bedroom. he suffocated her with a pillow. and then he stabbed her. clark used the scissors to remove her earrings which left the blood impression on the pillowcase. and in that blood, the partial thumbprint revealed by the black stain. there was no blood trail in the house since clark wrapped the body in bed linens and plastic. while transporting the body to the woods, he accidentally dropped the bloody pillowcase

with his thumbprint, later found by police. before dawn, he returned to clean up as much blood from the mattress as he could, found with the luminol. at daybreak, clark needed to exit the house without being seen, so he dressed up as laura. before leaving, clark made a second mistake. he used laura's hairbrush to comb his wig, leaving behind the single fiber linking him and his wig to the murder scene. later that day, he purchased a replacement bedsheet for laura's bed. he may have been on his way to replace it when he encountered laura's brother outside the home

the next night. a partial thumbprint and a single wig fiber all marked a grisly tail of murder, madness, and mistaken identity. >> he planned it. he knew exactly when he was going to do it. exactly how he was going to do it. he almost got away with it. >> of course, the bloody fingerprint on the pillowcase, the hair, the wig fiber. i was impressed with the dog. >> this was the only wig fiber that was recovered. if this had been missed or not even examined, it's very doubtful that we would have put together everything that we knew after the fact as to what actually happened on that monday morning. >> now with the new technologies that are helping us out, it allows an investigator to have new tools to help him find that little tiny bit of evidence that sometimes is there.

sometimes it's not. but when it is there, you have those tools, you're able to find that little bit of evidence. it makes all the difference in the world and allows you to get people like hadden clark off the when a two-year-old boy was rushed to the hospital suffering from brain seizures and breathing problems, doctors could not find the cause of the illness, but the boy's sister provided an important clue. the possibility of a rare syndrome few had ever heard of. in 1987 ray and tanya reed, along with their two children, had just moved to urbandale, iowa. it was ray reed's fourth job transfer in three years. >> every time we moved it was an advancementor