Donald Hayes was sitting at his desk in the Boston Police crime lab in the mid-1990s when the lieutenant running the cold case squad dropped a book in front of him: “The Boston Stranglers.”
Hayes had been a young boy north of Boston when a series of gruesome murders attributed to a serial killer terrified the region, and he knew only a little about the case. But he devoured the book — the latest to speculate that there were multiple killers — and soon shared Lieutenant Tim Murray’s desire to delve into a mystery that officials had more or less abandoned, even as it remained one of crime’s great enigmas.
Digging into the lab’s archives, Hayes wondered if he might find any surviving scrap of evidence that could be tested using modern methods to either exonerate Albert DeSalvo or provide the first physical link to any of the killings the smooth-talking laborer claimed he committed — a blanket confession made while awaiting trial for other crimes. Long after DeSalvo was stabbed to death in prison in 1973 doubts on that confession remained.
At first, Hayes found nothing, poking around in between working on evidence from many of the 1,200 new cases and more recent cold cases handled by the lab each year. Several of the Boston Strangler murders had been committed beyond the city limits; some of those inside Boston seemed to lead nowhere. Then Hayes found a cache of 16 boxes, their contents musty and uncatalogued, all related to the last heinous act in the crime spree allegedly committed by DeSalvo — the Jan. 4, 1964, rape and murder of Mary Sullivan.
Inside one box, Hayes discovered forensic-science gold: a maroon blanket marred with crusted stains and a few cuts from primitive testing decades earlier. Scraping a little bit off the blanket, mixing and staining the evidence onto microscope slides, Hayes soon found himself looking at decades-old sperm cells — possibly from the killer, but perhaps from a boyfriend of one of Sullivan’s roommates, or someone else.
He thought DNA testing might provide the answer. But the material proved to be too degraded and too old to extract a distinct DNA profile. More material would come his way, microscope slides from Sullivan’s autopsy unearthed at the state medical examiner’s office.
Hayes and his team tested some slides themselves and at a trusted outside lab, and tried again with material from the blanket. Still no luck. Eager to solve the puzzle but wary of using up the precious, microscopic supply, Hayes made a fateful decision: He locked the material away, believing that one day science would find a way to unlock their secrets. He could not know it would be more than a decade.
“I was confident as time progressed technology would progress to a point where we would be able to get information from these samples,” he said Thursday.
Years passed, but Hayes did not let the stored samples get far from his mind. In 2006, after Edward F. Davis was named police commissioner, Hayes told him about his dream of finding a distinct DNA profile in the Mary Sullivan evidence. Davis was hooked. “It was a long time ago, but nobody forgets it,” said Davis, who had devoured newspaper articles about the Boston Strangler as a grade school student in Lowell.
And whenever he spoke with Hayes about the sprawling work of the crime lab in the years that followed, talk often returned to the Sullivan evidence. Still, Hayes said each time, they needed to wait.
Meanwhile, Hayes — who with his short, pomaded hair and police-crest lapel pin could pass for a homicide detective but is a civilian employee — and his lab colleagues teamed with the cold case detectives to make breakthroughs on several more recent cases that had previously stumped police, harvesting DNA from evidence that dated back a decade or two.
Last year, he told Sergeant Detective William Doogan, the current head of the cold-case squad, it was time to try again with the Sullivan evidence. “He thought that the science had advanced to the point where we could take another shot at it,” Doogan recalled.
Meticulously, Hayes sent samples one at a time to independent outside labs and asked them to try different methods. The wait was excruciating, with police calling the laboratories daily. “Any word? Any word?” Doogan would ask.
Hayes contemplated safeguarding the last of the genetic material at police headquarters in case technology had still not advanced enough.
“If it comes up empty, we’ll know to back off,” Doogan said. “But we didn’t come up empty.”
Two labs, working separately, came back with a distinct profile for the same man, drawn from the blanket sample and from Sullivan’s autopsy. Now they had a DNA identity for the rapist and murderer. They just lacked a name.
The national database of DNA profiles taken from crime suspects in recent years returned no matches. Because DeSalvo had confessed, he remained the likely place to start in collecting a new sample for comparison.
The State Police, the Department of Correction, and the Norfolk County District Attorney’s Office, which investigated DeSalvo’s own killing, all tried to help. But no DNA could be extracted from envelopes he had licked when writing to prison and parole officials, Suffolk District Attorney Daniel Conley said.
Two options remained, Hayes advised detectives: Exhume DeSalvo’s body or obtain DNA from a male who shares his lineage, a living family member.
Rather than ask DeSalvo’s relatives, police worked in secret, so as not to alarm a family that has had an understandably tense relationship with law enforcement over the years. Officials worried that the relatives might guard themselves or flee.
So they tapped Sergeant Detective Brian Albert, head of the fugitive unit, specializing in suspect surveillance.
Albert initially set his sights on DeSalvo’s brother, according to Superintendent in Chief Daniel Linskey, but squad members watching his home never saw him exit and were unable to trail him.
They moved on to DeSalvo’s nephews, tracking them to Cape Cod and hanging out in plainclothes at restaurants and along beaches. Dozens of hours were logged as they waited for one of them to leave behind something that could provide a DNA match.
Finally, in January, one of the nephews — working construction for a hotel renovation — quenched his thirst and discarded the water bottle in a public place. Police grabbed it.
“Ten years ago, that water bottle — we would probably have gotten nothing off that,” Doogan said.
But they had waited, and now it paid off.
Globe reporter Maria Cramer contributed to this report. Eric Moskowitz can be reached at email@example.com.