Tamerlan Tsarnaev was mentioned several times as a person police should talk to after the men were found dead Sept. 12, 2011, in a Waltham, Mass., apartment, The New York Times reported Thursday.
Tsarnaev, who was killed in April in a shootout with police after the bombing, was a close friend of one of the deceased, Brendan Mess, 25.
Friends and relatives of the men contend police were quick to write off the deaths as a drug deal gone bad. Law enforcement officers familiar with the case say state and local police never questioned Tsarnaev, either as a potential suspect or as a source of information.
Tsarnaev was also implicated in the Waltham killings by his friend and boxing partner, Ibrahim Todashev, a senior law enforcement official said. Todashev had admitted his part in the killings, but was shot and killed during an FBI interrogation in Florida under clouded circumstances.
John Allan, owner of the gym where Tsarnaev and Mess worked out, and Tsarnaev's wife, Katherine Russell, both said Tamerlan seemed oddly unfazed by news of his friend's death.
"He laughed it off," Allan said.
A Massachusetts legislator who has closely followed the case defended the investigation into the Waltham deaths.
Rep. John J. Lawn said police work was "carefully done." There was a lack of clues and no signs of forced entry, leading police to believe someone the men knew and trusted committed the crimes, he said.