Brendan Mess case: Evidence suggests Tamerlan and Dzhokhar Tsarnaev were involved in unsolved triple murder in 2011

“Mounting evidence” gathered by investigators suggest Tamerlan and Dzhokhar Tsarnaev could have been involved in a grisly unsolved triple murder in 2011, it has emerged on Friday.

Officials told ABC News that forensic evidence could tie Boston bomber brothers Tamerlan and Dzhokhar Tsarnaev to the killings of Brendan Mess, Raphael Teken and Erik Weissman, who were found with their throats slit and marijuana dumped over their dead bodies in a Waltham, Massachusetts house.

The Tsarnaev brothers knew the men as Tamerlan trained in boxing and martial arts with Brendan Mass.

However, officials said more DNA testing is required before bringing an indictment against the surviving brother, Dzhokhar Tsaranaev, who is recovering from a self-inflicted gun wound in a prison infirmary.

Following the April 15 bombings and the suspected involvement of the Tsarnaev brothers, investigators began to look into the link between Tamerlan and Brendan Mess.

Authorities have now told ABC that forensic evidence from the crime scene in 2011 matches the Tsarnaev brothers. Their cell phones were also in the area at the time of the killings, records show.

The three men had ordered food from an Italian restaurant on the September 11, 2011, but when a delivery woman came to leave the food, no one answered the door.

The next morning, one of the victim’s girlfriends found their bodies.

Their throats had been slit, they have been covered with marijuana and there was also $5,000 cash in the home.

Initially police said two other people had been there on the day and they were looking to question them, although no one has ever been charged.

There had been no forced entry, so police believe the killer was known the victim and was let into the apartment.

Investigators at the time said the murders were “targeted and not a random act of violence”.

Middlesex District Attorney Gerard Leone issued a statement soon after the murders saying, “based on the present state of the investigation, it is believed that the victims knew the assailant or assailants, and the attacks were not random”.

Neighbors described Brendan Mess and his two roommates as quiet, nice people who were a welcome change of pace from previous residents who often had loud parties late into the evening.

After the deaths, friends said that Tamerlan Tsarnaev acted oddly – failing to attend his close friend’s funeral and dropping out of the martial arts school where they had both trained.

One man who knew Tamerlan Tsarnaev through the gym where they trained said some of their social circle “without even speaking about it beforehand have all been thinking” he could be involved.

The friend, who gave his name only as Ray, told BuzzFeed Politics: “At the time, none of us would have thought it was Tam. It was just so emotional and we thought we had someone else who had done it.”

But since Tamerlan Tsarnaev was identified as the suspect in the Boston Marathon bombings that killed three and injured 260, Ray believes his sudden disappearance after Brendan Mess’s death may be a clue.

“Tam wasn’t there at the memorial service, he wasn’t at the funeral, he wasn’t around at all,” Ray said.

“And he was really close with Brendan. That’s why it’s so weird.”

Tamerlan Tsarnaev was killed following a gun battle with police, a day after the FBI released images of him and his younger brother at the Boston Marathon.

His brother, 19-year-old Dzhokhar, was found hiding in a boat parked in a suburban yard and suffered a self-inflicted gunshot wound to the neck.

Dzhokhar Tsarnaev is now recovering and has been charged with using a weapon of mass destruction.