Today, July 19th, 2013—A nationally-recognized laboratory has matched DNA recovered from the body of Mary Sullivan almost 50 years ago with that of her suspected killer, officials announced today.
Suffolk County District Attorney Daniel F. Conley, Massachusetts Attorney General Martha Coakley, and Boston Police Commissioner Edward Davis today announced test results showing scientific certainty that the confessed “Boston Strangler,” ALBERT HENRY DeSALVO (D.O.B. 9/3/31), was the source of seminal fluid recovered at the scene of Sullivan’s 1964 murder.
Specifically, DNA specialists calculated the odds that a white male other than DeSalvo contributed the crime scene evidence at one in 220 billion. At the time Sullivan was killed, only about 3.2 billion human beings were alive on the planet, and only about 107 billion human beings have ever lived on the planet.
Sullivan, 19, was sexually assaulted and strangled to death in her Charles Street apartment sometime on the afternoon of Jan. 4, 1964. DeSalvo later confessed to that crime and about a dozen other murders, but recanted his admissions and was never convicted of any of them. Today’s announcement marks the first time that law enforcement officials could confirm his culpability in any homicide.
“I hope this brings some measure of finality to Mary Sullivan’s family,” AG Coakley said. “This leaves no doubt that Albert DeSalvo was responsible for the brutal murder of Mary Sullivan, and most likely that he was responsible for the horrific murders of the other women he confessed to killing. I want to thank District Attorney Conley, Commissioner Davis, and their teams for their work and for finally answering the lingering questions that have persisted for so many years.”
“We now have an unprecedented level of certainty that Albert DeSalvo raped and murdered Mary Sullivan,” DA Conley said. “We now have to look very closely at the possibility that he also committed at least some of the other sexual homicides to which he confessed. Questions that Mary’s family asked for almost 50 years have finally been answered. They, and the families of all homicide victims, should know that we will never stop working to find justice, accountability, and closure on their behalf.”
“This is a story about a relentlessness cold case squad that refused to give up, waiting until science met good police work to solve this case,” Commissioner Davis said. “The DNA test results provides a near certainty to what detectives working on the case knew all along, that Albert DeSalvo the suspect who confessed to sexually assaulting and strangling Mary Sullivan was likely her killer. I am proud of the tenacity shown by all of the detectives and analysts working on the case. The ability to provide closure to a family after 50 years is a remarkable thing.”
Officials announced the results today after notifying members of Sullivan’s family of the findings by technicians at Orchid Cellmark’s lab in Dallas, Texas.
Late last year, after advances in the sensitivity of DNA profiling led to increased success in extracting DNA profiles from very old, very small, and very degraded samples, the director of the Boston Police Crime Laboratory retrieved crime scene evidence from Sullivan’s homicide. That evidence included biological evidence recovered from two locations – the victim’s remains at autopsy and the blanket on which her body was found.
Slides containing the evidence from Sullivan’s remains were sent to Bode Technology, while cuttings from the blanket were sent to Orchid Cellmark. Separate technicians at those separate laboratories were able to extract DNA profiles from both sets of samples, and those DNA profiles matched one another.
The DNA profile was uploaded to the FBI’s Combined DNA Index System, or CODIS, which contains DNA profiles from millions of known offenders. There was no “hit,” ruling out at least one man who had earlier been an unofficial suspect in Sullivan’s homicide.
Given that DeSalvo confessed to Sullivan’s murder and recounted certain details of that crime with a high – but not perfect – rate of accuracy, investigators undertook a search for any remaining evidence that might contain his DNA. Neither the Department of Correction, which had custody of DeSalvo following his 1967 conviction; the Massachusetts State Police, which investigated his stabbing death at Walpole State Prison; the Norfolk District Attorney’s office, which prosecuted that homicide; nor the Office of the Chief Medical Examiner, which consolidated a county-based medical examiner system years after DeSalvo’s autopsy, had any suitable evidence, however.
Among modern advances in DNA technology is the comparison of Y chromosomes, which are passed down almost unchanged from father to son. Male descendants of the same father share almost identical Y chromosomes, which can be compared through testing of biological material. Bearing this in mind, Boston Police retrieved a water bottle that one of DeSalvo’s nephews drank from and discarded. That bottle was sent for comparison to the crime scene DNA, and the result, obtained earlier this year, was a match that implicated DeSalvo and excluded 99.9% of the male population.
To confirm the strong evidence that DeSalvo was Sullivan’s killer, however, authorities needed a confirmatory test. Last week, representatives of the Suffolk DA’s office, Attorney General’s office, and Boston Police obtained a search warrant to exhume DeSalvo’s remains from his Peabody grave. Even when suspects are identified through CODIS hits, authorities noted, investigators always seek a confirmatory DNA sample directly from the suspect to confirm the initial link.
On July 12, DeSalvo’s grave was excavated and his remains were transported to the Office of the Chief Medical Examiner. After suitable samples were taken, the remains were reinterred and the samples were sent for DNA extraction and comparison, leading to today’s announcement. The 21st century investigation was funded in part by a federal grant intended to help local law enforcement solve older crimes using modern scientific techniques.
A total of 11 homicides between 1962 and 1964 have been linked by law enforcement officials investigating the so-called “Boston Strangler.” The victims ranged in age from 19 to 67 and resided in the Back Bay, Beacon Hill, Brighton, Dorchester, Fenway, the South End, Cambridge, Lawrence, Lynn, and Salem. A map of the linked scenes can be viewed here. All of the victims were single women, all were sexually assaulted, and all were strangled with some form of ligature that the killer found at the scene. Though modern investigators have long sought biological evidence from the other crime scenes, none has yet been found.