Boston Strangler snared by DNA advances
Old-school detective work combines with the latest science to answer a 50-year-old question. Liz Porter investigates.
Fifty years ago Boston was a city in terror. Between 1962 and 1964, 11 women were raped and strangled in their apartments, usually with their own stockings. The killer was given many names, including the Mad Strangler, the Phantom Fiend and finally the Boston Strangler, but his true identity was not conclusively known until July this year.
A group of Texas-based DNA scientists made world headlines by proving that Albert DeSalvo – a man who half a century earlier claimed to be the Strangler – had definitely killed one victim. How the link was confirmed is a tale of CSI meets calm, old-fashioned persistence.
At the time of the killings, Boston was anything but calm. Police and prosecutors were under immense pressure to bring the murder spree to an end quickly. Every known sex offender was hauled in and interviewed, but none could be linked to the crimes. Then, less than a year after the Strangler murdered his last victim, the police believed they had found their man: small-time burglar and rapist Albert Henry DeSalvo. Already behind bars and eventually to receive a life sentence for another series of rapes, DeSalvo “confessed” to a cellmate that he was indeed the Boston Strangler. Later he recanted. Given that DeSalvo was a known braggart, and lacking any forensic evidence linking him to any of the crimes, he was never charged.
In 1973, DeSalvo was murdered by a fellow inmate, but the case of the Boston Strangler lived on. Different theories emerged. Some argued that multiple killers were at work; others exonerated DeSalvo. For Hollywood it was an open and shut case. Actor Tony Curtis not only won a Golden Globe for his role as Albert DeSalvo in the 1968 film The Boston Strangler, he cemented him as the culprit in the public consciousness. But as far as legal evidence, it seemed the Boston Strangler’s secret went with him to the grave.
Fast-forward 30 years to the late 1990s, and the Boston police crime lab. Its director Donald Hayes had just read Susan Kelly’s 1996 book on the Boston Strangler that claimed there were at least eight different perpetrators and DeSalvo wasn’t one of them. He was intrigued. Could modern forensic science finally crack the case? Hayes scoured the lab’s archives for physical evidence from the murder scenes. He found a cache of boxes from the Strangler’s last victim, 19-year-old Mary Sullivan. One contained the maroon blanket on which she’d been found; it was stained with seminal fluid. In addition the state medical examiner’s office still had slides, taken at Sullivan’s 1964 autopsy, which contained her assailant’s semen. But attempts to extract DNA from this material in 1999 and 2001 failed and destroyed part of the precious evidence. Hayes decided to lock the samples away until DNA technology had advanced.
By 2012, he judged the time was ripe. He sent a sample of the semen collected at autopsy to Virginia-based forensic lab, Bode Technology. He also sent cuttings from the blanket to DNA-testing company Orchid Cellmark in Texas. Both samples produced the same DNA profile. It was run against the FBI’s Combined DNA Index System, containing profiles from millions of offenders. There was no match.
It was time to compare the DNA in the semen samples to a profile from DeSalvo. But the Boston police lab had no tissue samples that might contain his DNA. An exhumation was the only sure way to get it, but Hayes needed evidence if a court was to order one.
So he looked to family members. If DeSalvo was the source of the semen, his brother’s son Timothy might prove it. Timothy would have inherited the same Y-chromosome that DeSalvo carried. Considering the DeSalvo family to be uncooperative (an allegation strongly denied), police covertly followed Timothy and when he discarded a water bottle, they helped themselves. His Y-chromosome DNA matched that of the semen taken from Mary O’Sullivan’s body and the maroon blanket. It wasn’t a conclusive identification of DeSalvo as the Strangler, but it was enough to order an exhumation of his body. Samples from his teeth and femur were sent to Orchid Cellmark. His DNA provided an extraordinary match to that in the semen samples: the odds that it belonged to a white male other than DeSalvo were one in 220 billion.
After half a century, science had finally nailed the Boston Strangler.