It seems the Tsarnaev brothers may have been bad seeds long before the Boston bombings. Law enforcement officials are gathering what they call “mounting evidence” that both Tamerlan and Dzhokhar Tsarnaev were involved in a grisly triple murder in 2011. Middlesex County, Mass., investigators tell ABC News that forensic evidence and cellphone records link both men to the slaying of Brendan Mess and two associates in Waltham, Mass., who were found with their throats cut and their bodies covered in marijuana. If the case is strong enough, officials could indict Dzhokhar Tsarnaev with these killings as well as the three bombing deaths, for a total of six murder charges.
2011 Waltham Murders
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The three men, who were described as being physically strong, were dragged to or killed in three different rooms. Mess was a well-known mixed martial arts fighter, and is listed as a martial arts instructor on his death certificate. Teken is listed as a personal trainer on his death certificate. Weissman was a bodybuilder.
In 2008, police pulled Weissman over for failing to yield and smelled marijuana smoke in his vehicle. When questioned about it, Weissman said, "I knew you would smell it", and handed the officer a brown paper bag filled with bags of marijuana, police said. He was charged with marijuana possession and intent to distribute. Teken lived in Waltham, where certain neighbors said they believed he was a drug dealer, saying he rarely left the house and had a steady stream of visitors. In 2010, Mess and another man were arrested on charges that they assaulted several people at a store.
2011 investigation 
Autopsies revealed that the men had been brutally murdered. Their heads had been pulled back, and their throats had been slit from ear-to-ear with either an ice pick or knife with such great force that they were nearly decapitated. Their mutilated bodies had been left covered with thousands of dollars worth of marijuana (seven pounds of marijuana; in what investigators described as a symbolic gesture) and thousands of dollars of money, in three different rooms. Police said $5,000 was left at the scene, which suggested that robbery was not the motive.
No motive was discovered, though the police said that the murders were not random. Two unidentified men had been seen at the apartment before the murders.Middlesex District Attorney Gerry Leone said that it appeared that two unknown perpetrators and the victims knew each other, based on evidence that the police had obtained. It was believed that there was more than one person at the scene other than the victims based on "many factors," and that the victims let the killers into their apartment, and there was no evidence of forced entry. Neighbors whose windows were open did not hear any signs of trouble.
A Waltham police investigator said the murders were: