the tourist season in virginia's chesapeake bay did not get off to an auspicious start. serrano: the story started when a family out boating in the chesapeake bay found a suitcase floating on the water. they brought it up onto the deck, thinking that it was buried treasure. the family opened it up and they found two human legs inside the suitcase. narrator: the legs, wrapped in black plastic bags, were from an adult male. news of this gruesome discovery spread quickly throughout the area. miller: that's not a crime that's typical, to have somebody dismembered and thrown at sea like that. obviously, it's foul play. this is not an accident. narrator: the community wanted answers, but six days later, all they got was more questions. on the shore of an island next to the chesapeake bay bridge and tunnel, another suitcase was found. dunton: opening up the suitcase, there were more black trash bags similar to the first one.

peeling back the trash bags, it revealed a torso of a white male. the torso contained the arms, hands, and head of the white male. narrator: as with the body parts in the first suitcase, there was no way to identify the remains, but the contents of the second suitcase at least provided some clues to the victim's identity. the description -- white male between 25 and 35, about 180, 160 pounds, a short-cropped military haircut, but no other scars, marks, or tattoos. narrator: in addition to the plastic bags that wrapped the body, there was a hospital blanket around his head. an autopsy on the remains indicated the likely cause of death. we x-rayed the torso and found that there was an entrance exit through his head and then two bullet wounds to his chest cavity. prezioso: the second suitcase, the largest suitcase -- that probably had the most amount of evidence in it.

recovered in there were two projectiles, .38 caliber. narrator: where was the rest of the body? the answer came five days later, when yet another suitcase was found floating in the bay. miller: by the time we got the third one, we just we stuck it on board and took it straight back. narrator: the rest of the victim was in the third suitcase. gas created by decomposing body parts caused the suitcases to float to the surface. dna testing on those remains showed they were all from the same person, but that dna did nothing to identify who he was. we ran it through the virginia dna databank, but unfortunately, there was no identification in there. narrator: but while investigators knew next to nothing about their victim, the skill with which he'd been dismembered revealed possible clues about his killer. it did look surgical. it looked very neat, like somebody did have some sort of medical knowledge.

narrator: since investigators had few options, they took an unusual step. even though the victim's head had been submerged in salt water for at least two weeks, they commissioned a forensic sketch in an attempt to determine his identity. higgins: they had a drawing made of the victim as best they could, and they televised it on the local morning news. ♪

narrator: when three suitcases containing body parts were plucked from the chesapeake bay, investigators were eager for any evidence they could find. though there were three bullet wounds, only two slugs from a .38 caliber were recovered from the body. one of them was covered with green cotton fibers. the three suitcases containing the body parts were from a matching set. the plastic bags that wrapped the body appeared to be similar. the body parts were wrapped in black garbage bags. they were tied with blue painter's tape. narrator: the blanket that wrapped the victim's head was distinctive. prezioso: it was like a white or cream colored blanket with an hcsc tag. we learned that hcsc is a company that provides medical linens to hospitals and doctors offices. narrator: the first step was to at least attempt an identification.

the victim had been in salt water for weeks, and his face was decomposing. investigators took a photograph of the face and gave it to a forensic artist. the sketch seemed like a long shot. narrator: in addition to basic facial features, key details like eye color, race, and a reasonable estimate of age could be determined. the resulting sketch and additional information was broadcast on local television, and police soon got a call. it's mindblowing to think that these people actually recognized him. the tipster said she thought the man was bill mcguire. she and her husband knew him when he was stationed in virginia with the navy. fingerprints confirm this hunch. mcguire was a 39-year-old computer programmer and father of two young children who had been living in new jersey. he was described as loyal to his friends, loving to the people around him, a lot of fun.

he seemed to be a regular guy. narrator: at the time bill mcguire was identified, he'd been missing for four weeks, so investigators' first question was, "had anyone been looking for him?" his wife never reported him missing, but there was concern about his location. narrator: his wife, melanie, said there was a good reason she didn't file a missing persons report. melanie said to police that her and bill had a terrible fight in which he became physical, stuffed a dryer sheet in her mouth, pushed her up against the wall, and then left the home. according to melanie, bill told her, "you'll never see me again." narrator: in fact, instead of reporting her husband missing, melanie mcguire got a restraining order against him. and when asked who she thought might want bill dead, she said she didn't know, but that bill spent a lot of time and money gambling in atlantic city.

we did find that he enjoyed gambling. new jersey is a gambling state. we have a very heavily regulated, legalized gambling system, and at the time, it was really solely located in atlantic city. narrator: this jibed with the potential break in the case. detectives ran bill's license plate number and discovered his car in an impound lot in atlantic city. surveillance video from the night bill was last seen showed the car being parked at the flamingo hotel. when the video was examined, we couldn't identify who had parked the car. narrator: this was a setback, but bill's car was proving to be a rich source of evidence. the car in atlantic city ended up being critical. in the glove compartment was a small vial of pink liquid. we could not figure out what was in the vial for some time. it became very frustrating. narrator: and even though there were no foreign fingerprints in the car,

analysts found something else that could help their case. they vacuumed both the driver's side rug and the passenger side rug in the front seat. those vacuumings were later analyzed, and they found small -- very small -- pieces of flesh. we bring in an expert and he finds what he called human sawdust. narrator: this was microscopic bits of skin and flesh. unfortunately, it's gruesome, but it's also accurate. it was human sawdust. it was tested, and it was a positive match for bill mcguire based on nuclear dna. there were skin cells that had fallen onto the floor that you're not gonna be able to see, and whoever drove his car to atlantic city then transferred them onto his floorboard. narrator: but since the surveillance video couldn't identify the driver, this was looking like a dead end. the case that had been moving forward now stalled.

♪

he search for bill mcguire's killer, a vial and a syringe containing a pink liquid that was found in the glove compartment of his abandoned car confounded investigators. prezioso: it became very frustrating. we couldn't figure out what it was. narrator: meanwhile, investigators checked out the possibility that bill's gambling might have led to his murder, and they got a bit of a surprise.

bill mcguire was known to the casinos. he went there a lot, and he was a very disciplined gambler. narrator: in fact, bill wasn't in debt from gambling. he was firmly in the black. higgins: the last time he had been down in atlantic city, he had won a jackpot of $30,000. so, he had done very well for himself. narrator: not only that, in a weird irony, on the last day bill was seen alive, he and his wife melanie put a down payment on a half-million-dollar house. serrano: he was a very goal-oriented person. one of his goals was to own a home before he turned 40. and he achieved that dream. narrator: so, who would want him dead? ballistics showed he'd been shot with a .38-caliber gun, which still had not been located. did anybody in bill's circle have a gun? investigators went through all bill's known contacts to see if anyone owned a .38-caliber gun, and someone did.

his wife, melanie. prezioso: melanie mcguire had purchased a gun in pennsylvania two days before bill went missing, and what she had purchased was a .38-caliber taurus special revolver. narrator: melanie said she bought the .38 caliber because bill told her to. he wanted some extra protection when they moved into the new house. and melanie, a killer? no one who knew her was buying it. she was a highly respected reproductive nurse with no criminal history. from all reports, she was a wonderful nurse. higgins: she seemed to have been very popular where she worked. she was very efficient. people liked her. narrator: melanie denied having anything to do with her husband's murder, but this was the same melanie who intimated bill might have a gambling problem, which wasn't exactly true. and she said they had a horrific fight the day he disappeared. was this also false?

melanie's work as a nurse also presented a possible tie to the murder. serrano: and there was the hospital blanket found wrapped around william mcguire's face from that company known as hcsc, which supplied blankets and other things to melanie mcguire's fertility clinic. narrator: the blanket, and more importantly, the purchase of the .38-caliber gun gave investigators enough to put a wiretap on melanie mcguire's phone. and this introduced a new player into the mix. his name was dr. bradley miller. he worked with melanie at the fertility clinic. and their phone calls indicated a relationship that went well beyond work. serrano: bradley miller was melanie mcguire's lover, and that affair had lasted more than two years and was what was called a very intense love affair. narrator: could this affair finally provide the motive

for bill mcguire's murder? higgins: and we put it together. she purchases a house with a husband which will strap her for 30 years financially when she really wants to be with this doctor. narrator: access to the fertility clinic helped answer the question about the so-far unidentified drug found in bill mcguire's car. a prescription from dr. miller's office had been filled the day bill was last seen alive. it was for a substance called chloral hydrate, a sedative sometimes administered just before surgery. so, chloral hydrate was what you would read about in detective novels from the 1940s, known as a mickey finn or knockout pills. narrator: forensic testing showed this was the pink substance in the syringe found in bill's car. chloral hydrate is not used in reproductive medicine. narrator: but it would be very effective if you wanted to knock someone out before killing them

and cutting up their body. the reputation of chloral hydrate is that it's used for nefarious reasons. ♪

narrator: detectives investigating the murder of bill mcguire

were focused on the sedative chloral hydrate found in his abandoned car. prezioso: there was a prescription for chloral hydrate filled on the day that bill was last known to be alive at the walgreens pharmacy one and a half miles away from where melanie had just dropped off her children. narrator: and that prescription was written on the pad of dr. bradley miller, a fertility doctor who'd been carrying on an affair with melanie mcguire for more than two years. but when shown the chloral hydrate prescription, dr. miller said someone had forged his signature, and it looked like the forger could be melanie mcguire. we found out, did she have access to prescription pads? and indeed, she did. dr. miller freely admitted to the affair with melanie, but strenuously denied having anything to do with her husband's murder, and he was eager to prove it. higgins: he is what we call a consensual, where he records conversations with her to see

if they can't get to the truth of what she had done. when dr. miller pressed melanie in these conversations, she got very cagey. morris: what we learned from listening shocked some seasoned detectives, that we were dealing with a very cunning and chilling woman. narrator: but in another of the wiretap calls, melanie made a crucial mistake. she admitted that she was the person who parked bill's car in atlantic city after the murder.

and that meant the nearly invisible human sawdust found in bill's car was almost certainly tracked there by melanie. it was hugely significant evidence, that there were pieces of bill's flesh recovered from the car that was parked at the flamingo hotel, and melanie mcguire herself admits that she's the one who parked it there. narrator: the question now was, "where was bill killed and dismembered?" a team of forensic analysts descended on the mcguires' apartment, but this was months after the murder and melanie and the kids had already moved out. dunton: the apartment was immaculate. it was cleaned. it was scrubbed. it had been repainted -- like, three or four coats of paint. narrator: no proof of murder was found there, not even, to the surprise of forensic technicians,

in the bathrooms. dunton: bathrooms are like petri dish for forensic biology, and not one single source of dna was recovered from the bathroom area. narrator: analysts now turn to the black garbage bags found with bill's body. after his murder, melanie gave some of his clothes to a family friend and packed them in black garbage bags. we learned that these garbage bags were made from reprocessed plastic. narrator: which meant the chemical composition of these bags was distinctive, and in this case, both sets of bags, the ones found with bill's body and the ones melanie used to pack his clothes, were chemically consistent. even worse for melanie, as plastic is cut to make individual bags, a blade leaves distinctive tool marks along the perforated edge of each bag. as the blade dulls, those marks change. bags cut within seconds of each other will have nearly identical marks, and these did.

morris: we matched them to the bags that were found in the suitcases with the body parts. narrator: prosecutors say melanie bought the .38 caliber two days before the murder and bought it for one reason -- to shoot her husband. she slipped the chloral hydrate into his drink to incapacitate him, then she shot him three times. fibers on one of the bullets had police believing she used a pillow as a silencer. her medical background gave her the knowledge she needed to expertly cut up the body. she wrapped the body parts in black plastic bags that were consistent with bags she later used to pack bill's clothes. in a key mistake, she later admitted on the police wiretap that she drove bill's car in atlantic city right after the murder, but her being in the car explained how the so-called human sawdust got there. she unknowingly tracked it on the soles of her shoes. she drove nearly 350 miles and dumped the suitcases

with the body parts into the atlantic, not realizing that decomposition would cause those suitcases to rise to the surface. all the evidence pointed in one direction -- to a woman whose passion to be with her lover and away from her husband led to an indescribably brutal murder. if she's having an affair, why wouldn't she just divorce him? but the thing is, murder is never reasonable. serrano: i think that was part of the public's fascination with the case. you had this compassionate woman on one side and this diabolical killer on the other side. narrator: in july of 2007, after a seven-week trial with more than 80 witnesses, melanie mcguire was found guilty of first-degree murder and sentenced to life in prison. dr. bradley miller was found to have no connection to the murder. the mcguires' children are being raised by bill's sister.

melanie still maintains her innocence, but investigators say the mountain of forensic evidence leaves no doubt that this most unlikely of suspects killed and cut up her husband. people who think that they're criminal masterminds usually forget something, and in this case, melanie mcguire forgot to wipe off the bottom of her shoes. to look at her, you wouldn't think that she was capable of doing this. it's only when you put it all together that you come to that determination. prezioso: the forensic evidence was the whole case. i can tell you, i believe that justice was done in this case, and absolutely the right person is in jail today. ♪ -oh, there's the captain. -captain jack.

narrator: up next, everyone in town knew the local handyman. he was really tough, hardworking. really look up to him. narrator: his vicious murder makes no sense to anyone. somebody has to have an answer. the motive in this case was tragic. narrator: a crime this violent creates evidence, and some of it can't be hidden. the jury wants to see things other than testimony. they want to see forensics. narrator: and those forensics point to a pillar of the community. people had been talking to him about potentially running for governor. ♪ ♪ narrator: the town of derry is nestled in the southern part of new hampshire, just across the border from massachusetts. it's always been known as sort of a working-class town.