The man who confessed to but was never convicted of the "Boston Strangler" murders that terrified this city 50 years ago did commit at least one of the attacks, Massachusetts prosecutors said on Friday, citing new DNA evidence.

A week after the body of Albert DeSalvo was exhumed for further DNA testing, the tests confirmed that he killed 19-year-old Mary Sullivan, in January 1964, the last of 11 victims attributed to the Boston Strangler.

"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," Massachusetts Attorney General Martha Coakley said in a statement.