Tsarnaev 2011 murders? Boston-bombing brothers also could be linked to earlier deaths.

Ever since investigators solved one big mystery in April – identifying Tamerlan and Dzhokhar Tsarnaev as suspected Boston Marathon bombers – an important new mystery has hung in the air: Did one or both of the brothers also have a role in an unsolved 2011 case of triple murder?

Now, some news reports say law enforcement officials are closer to making a connection.

In hindsight, one salient detail may be this: It was on Sept. 11, precisely on the 10th anniversary of the 9/11 terrorist attacks on the United States, that three men were killed in a Waltham, Mass., apartment.

Two news organizations are reporting that local investigators are delving into forensic evidence and cellphone records that may link one or both brothers to the homicide.

The Boston outlet of Fox News cites sources with knowledge of the investigation, saying that Tamerlan’s cellphone “was used near the murder scene on the day of the triple homicide and his fingerprints were found inside the apartment.” But the sources caution that those details don’t provide any definitive link between him and the crime.

ABC, similarly, says “some crime scene forensic evidence provided a match to the two Tsarnaev brothers” and that cellphone records put both brothers “in the area of the murders on that date.”

Tamerlan was friends with one of the victims, Brendan Mess. They were once roommates and did boxing and martial arts training together, ABC reported.

The crime scene was gruesome. The victims were found with their necks slit and their bodies reportedly strewn with marijuana.

The crime occurred after a period in Tamerlan’s life when, according to news reports, he had hit roadblocks in his aspirations to become an Olympic boxer, given up drinking and smoking because of his Muslim religion, and grown more radical and impassioned in his religious views.

Some acquaintances of the younger Tsarnaev brother, Dzhokhar, have described him as a marijuana user who did not show outward signs of radical religious views.

In searching for possible motives, investigators are looking into whether one of the brothers was involved in moving drugs, owed money, or was owed money.

The Boston Marathon bombings on April 15 killed three and injured more than 260 people. Tamerlan was killed in a shootout with police early on April 19, and his body was laid to rest this week after a lengthy search for a cemetery willing to serve as a burial site. According to news reports, Tamerlan was buried in an unmarked grave in a Muslim cemetery in Doswell, Va. 

Dhzokhar was captured later on April 19, and is awaiting trial for helping to set the twin bombs.