A former medical student accused of killing a masseuse he met through Craigslist committed suicide in the Boston jail where he was awaiting trial, authorities said Sunday.

Philip Markoff, 24, was found unresponsive in his cell Sunday morning in the Nashua Street Jail, the Suffolk County district attorney’s office said in an e-mailed statement, and he was pronounced dead at about 10:15 a.m.

“Markoff was alone in his cell, and all evidence collected thus far indicates that he took his own life,” the statement said.

Authorities will investigate to determine the facts and circumstances surrounding his death, the district attorney said.

Saturday would have been Markoff’s first wedding anniversary, but his nuptials were canceled after his arrest.

Markoff, a former Boston University student, pleaded not guilty in the fatal shooting of Julissa Brisman, of New York City, and the armed robbery of a Las Vegas woman. Both crimes happened at Boston hotels within the span of four days in April 2009. Rhode Island prosecutors also accused him of attacking a stripper that week.

His trial in the Massachusetts cases was expected in March.

Markoff’s lawyer, John Salsberg, said he was shocked and saddened about his client’s death. He would not comment further.

Markoff had met the women through advertisements for erotic services posted on Craigslist, a classified advertising Web site, prosecutors said.