Boston in the early 1960s was a city of triple-decker houses, working-class neighborhoods, and university campuses. It was also, for two and a half years, a city in the grip of a particular, paralyzing fear — the kind that makes women double-lock their doors and check their windows before sleeping. Thirteen women were murdered in their apartments between June 1962 and January 1964. The press called the killer the Boston Strangler. For decades, the truth of who he was, and whether one man had done it all, remained contested. The answers, when they came, arrived not from a courtroom but from a laboratory.

Thirteen Victims, Two and a Half Years

The murders began on June 14, 1962, when 55-year-old Anna Slesers was found strangled in her apartment on Gainsborough Street. Over the following months, women across the Boston metro area — in Cambridge, Salem, Lawrence, and Boston proper — were found dead in their homes. They ranged in age from 19 to 85. Most were sexually assaulted. Most were strangled with articles of their own clothing, often tied in a deliberate bow at the throat. The apartment doors showed no sign of forced entry, suggesting the victims had opened them willingly. The final victim attributed to the Strangler was 19-year-old Mary Sullivan, found in her Charles Street apartment on January 4, 1964.

Albert DeSalvo: The Man Who Said He Did It

Albert DeSalvo was already in custody on sexual assault charges — he had previously been arrested for a series of home intrusions he called the “Measuring Man” crimes — when, in 1964, he began confessing to the Strangler murders to his attorney, the renowned F. Lee Bailey. His knowledge of the crime scenes was striking: he described the apartments, what the victims wore, the positions in which he had left them. Through Bailey, DeSalvo provided details investigators found convincing. Yet the legal situation was paradoxical. Because his confessions were made to his attorney and could not be directly used against him, and because physical evidence tying him to the murders was thin, DeSalvo was never charged with any of the Strangler killings. He was convicted in 1967 of unrelated rapes and sentenced to life in prison. He was stabbed to death in his cell at Walpole State Prison in November 1973 by an unknown assailant.

Decades of Doubt

Almost from the beginning, investigators and legal experts questioned whether DeSalvo was truly responsible for all thirteen murders — or even any of them. The crimes had notable inconsistencies. The victims ranged in age so dramatically that criminologists questioned whether a single offender was responsible for all of them. DeSalvo’s motive for confessing was never fully clear; some speculated he sought notoriety or hoped that a murder confession might lead to a more favorable legal or psychiatric outcome. The family of Mary Sullivan, the final victim, was among the most vocal skeptics. They retained investigators and attorneys for years, convinced that the true killer had never been identified.

The 2013 DNA Breakthrough

In 2013, Boston law enforcement — working with the Sullivan family and the National Institute of Justice — pursued a new forensic approach. Investigators obtained DNA from a water bottle discarded by one of DeSalvo’s nephews. They compared its Y-chromosome profile — passed nearly unchanged through the paternal line — to DNA extracted from biological evidence recovered from Mary Sullivan’s body. The familial match was significant. Authorities then exhumed DeSalvo’s remains from his grave in Peabody, Massachusetts. DNA extracted directly from his femur and three teeth was compared to the crime scene evidence. The match was conclusive. On July 19, 2013, Boston Police confirmed that Albert DeSalvo had raped and murdered Mary Sullivan. The statistical probability of another white male being the source was calculated at one in 220 billion.

What the DNA Did and Didn’t Resolve

The 2013 confirmation settled one question definitively: DeSalvo had been present at Mary Sullivan’s murder. But it did not fully resolve the broader controversy. Whether he was responsible for all thirteen attributed murders remains a matter of forensic debate. Investigators have never conclusively linked DeSalvo to each case with the same evidentiary weight. The National Institute of Justice noted the case as a landmark in the use of DNA genealogy to close cold cases — a methodology that would later be applied in cases like the Golden State Killer. For the Sullivan family, the result was bittersweet: confirmation of what they had long believed, arrived fifty years too late for a trial.

Why This Case Still Matters

The Boston Strangler case is a study in the limits of confession-based justice. DeSalvo spent years in prison for crimes he was never formally convicted of committing — and yet the 2013 DNA evidence confirmed that at least one of those confessed murders was real. The case also illustrates how fear can shape a city: the Strangler’s reign drove women across Boston to change their behavior, their housing choices, and their relationship with urban life. It gave rise to some of the earliest organized victim-safety programs and spurred legislative discussions about sexual predator registries. The methodology used to finally confirm DeSalvo’s guilt — familial DNA, cold-case exhumation, comparative genomics — has since become a standard tool in unsolved case investigations worldwide.

Albert DeSalvo died without ever standing trial for a single murder. The women he killed died in their own apartments, in a city that prided itself on community and civilization. The science that finally confirmed his guilt did not exist when he confessed, or when he was imprisoned, or when he was buried. Fifty years had to pass before the truth settled — not in a courtroom, but in a test tube. And still the question hangs: for the victims whose cases remain unconfirmed, will that kind of certainty ever come?