42°22′36″N 71°13′03″W / 42.376736°N 71.217405°W / 42.376736; -71.217405

A triple homicide was committed in Waltham, Massachusetts, in the United States, on or very near to the evening of September 11, 2011. Brendan Mess, Erik Weissman, and Raphael Teken were murdered in Mess's apartment. All had their throats slit with such great force that they were nearly decapitated. Thousands of dollars' worth of marijuana and money were left covering their mutilated bodies; in all, $5,000 was left in the apartment. The local district attorney said that it appeared that the killer and the victims knew each other, and that the murders were not random.

Tamerlan Tsarnaev, the now-deceased co-perpetrator of the 2013 Boston Marathon bombing, had previously described murder victim Brendan Mess as his best friend, though before Mess was murdered there had been animosity between Tsarnaev and Mess over Mess's "lifestyle". After the bombings and subsequent revelations of Tsarnaev's personal life, the Waltham murders case was reexamined in April 2013 with Tsarnaev as a new suspect. Authorities said Tsarnaev and his younger brother Dzhokhar Tsarnaev may have also been responsible for the triple homicide, that forensic evidence connected them to the scene of the killings, and that their cell phone records placed them in the area. While police in the first investigation said that victims were killed on September 12, The Boston Globe, Boston Herald, and The Wall Street Journal reported that at least one relative of the victims believes that the killings took place on September 11.

In May 2013, Ibragim Todashev, a 27-year-old Chechen native and former mixed martial arts fighter who knew Tamerlan Tsarnaev, was shot and killed in Orlando, Florida, by law enforcement officers who had been interviewing him about the Waltham murders as well as the Boston Marathon bombings. The FBI has alleged that just before he was killed, Todashev made statements implicating both himself and Tamerlan Tsarnaev in the Waltham murders—saying that the initial crime was a drug robbery, and the murders were committed to prevent being identified by the victims.

All three victims were Jewish according to a number of sources. Other sources have not reported a religion for Mess. Weissman was outspoken about his Jewish faith, and an active member of his synagogue. Teken had majored in history at Brandeis University; he was buried in Israel.

Mess had been described by Tamerlan Tsarnaev as his best friend. Mess, Weissman, and both Tsarnaev brothers had attended Cambridge Rindge and Latin School at various times. Mess received a bachelor's degree in professional writing from Champlain College in 2008.

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 was listed as a martial arts instructor on his death certificate. Teken was listed as a personal trainer on his death certificate. Weissman was a bodybuilder.

In 2008, police had pulled Weissman over for failing to yield, and smelled marijuana smoke in his vehicle. 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.