BOSTON — Investigators said Thursday that they had linked the man believed by many to have been the Boston Strangler to DNA found in the home of a woman thought to be the Strangler’s last victim in a string of unsolved murders that petrified this city in the early 1960s and has perplexed it ever since.

Over the course of about 20 months from 1962 to 1964, 11 women ages 19 to 85 were brutally murdered here and in nearby cities, many sexually assaulted and killed in their homes. Mary Sullivan, 19, the last of the victims, was found raped and murdered in her apartment in January 1964.

“We may have just solved one of the nation’s most notorious serial killings,” said Martha Coakley, the Massachusetts attorney general, at a news conference at Boston Police Headquarters.

District Attorney Daniel F. Conley of Suffolk County said investigators, who included members of the Boston Police Department’s cold case team and the attorney general’s office, had recently tested seminal fluid samples taken from Ms. Sullivan’s body, and the blanket on which it was found.