(CNN) — The body of longtime Boston Strangler suspect Albert DeSalvo will be dug up for DNA tests that investigators expect will prove he killed the last of the Strangler’s victims, Massachusetts authorities announced Thursday.
DNA taken from a water bottle thrown away by one of DeSalvo’s nephews is a “familial match” with genetic material preserved in the 1964 killing of 19-year-old Mary Sullivan, Suffolk County District Attorney Dan Conley said.
“This is good evidence, strong evidence and reliable evidence, but it’s not sufficient to close the case with absolute certainty,” Conley told reporters. He said DNA from DeSalvo’s remains is needed to prove “once and for all” that the onetime handyman was Sullivan’s killer — and perhaps to close other cases to which DeSalvo confessed.
A judge has approved the exhumation of DeSalvo’s remains, and testing could be complete within “a matter of days,” Conley said.
DeSalvo confessed to 13 of the killings, including Sullivan’s, but was never charged with them. He was sent to prison for unrelated rapes and was stabbed to death there in 1973.
No physical evidence available at the time connected DeSalvo to the crimes, and critics said some of the details DeSalvo provided to police were from news reports or police. But former prosecutor Julian Soshnick told CNN in 2002 that DeSalvo “knew things that were not in the public domain.”
“I’m absolutely certain that he was the Strangler, that he was without any doubt the Strangler,” Soshnick said.
Conley said scientists tried several times in the late 1990s and early 2000s to isolate DNA evidence from semen found in Sullivan’s body and on a blanket. They resumed their efforts last year, after a laboratory successfully salvaged DNA from decades-old material, and found what they believe is the unique genetic profile of Sullivan’s killer.
But despite an exhaustive search, investigators found no usable samples of DeSalvo’s DNA. So detectives followed male DeSalvo relatives until one nephew, who wasn’t named during the news conference, discarded his water bottle. That gave detectives the evidence they needed to seek DeSalvo’s exhumation.
Conley said authorities didn’t ask the DeSalvo family for their cooperation, hoping to save them “a great deal of anxiety.” But he defended the secret collection of their DNA as “a fair and legal and ethical method,” and said police and prosecutors had explained their moves to the DeSalvo family before Thursday’s announcement.
“It was difficult in some ways but, I hope, sets the stage for closure that eluded them for more than twice as long as Mary Sullivan lived on Earth,” he said.
DeSalvo was about to recant his confession before he was killed, his brother, Richard DeSalvo, said in 2001. Richard DeSalvo had offered blood and saliva samples at that time in hopes of proving his brother’s innocence.
“I honestly swear, on a stack of Bibles, there’s no way in the world he was the Boston Strangler,” Richard DeSalvo said.