Tamerlan Tsarnaev shown in February 2010. (Julia Malakie/The Lowell Sun via Associated Press) (Julia Malakie/AP)

Authorities in Massachusetts are investigating whether one of the Boston Marathon bombing suspects is connected to a triple murder in the city of Waltham that occurred in September 2011, according to prosecutors.

MaryBeth Long, a spokeswoman for the Middlesex County district attorney’s office, told The Washington Post that the homicide case “remains an active and ongoing investigation. We continue to follow all leads and will review any new information that may come to light in that case as a result of the investigation into the alleged bombing suspect, Tamerlan Tsarnaev.”

She declined to comment further, citing a policy of not discussing open cases. The Boston Globe reported that Tsarnaev, who was killed in a shootout with police, was friends with one of the victims, Brenden Mess, 25.

The newspaper also said that family members of one of the victims said the killings occurred the night of Sept. 11, 2011, the 10th anniversary of the attacks in New York and at the Pentagon. Authorities, including Long, said the three men were killed early Sept. 12.

A statement from the Middlesex County district attorney’s office said Mess, of Waltham, Erik Weissman, 31, of Cambridge and Raphael Teken, 37, of Cambridge, were found dead in an apartment the afternoon of Sept. 12.

A statement from police issued at the time said detectives believed the attack was not random and that the victims knew their attacker. The Globe has reported that the killings appeared to be drug related and that the victims’ throats were slashed.