Massachusetts investigators have developed mounting evidence, bolstered by forensic hits, that point to the possible involvement of both Tamerlan Tsarnaev and his younger brother Dzhokhar in a gruesome, unsolved triple homicide in 2011

In the wake of the Boston Marathon bombings, Middlesex County began to probe a link between the elder Tsarnaev and Brendan Mess, one of the three men killed in the gruesome slaying on September 11, 2011. Officials said that Mess and two men were found in a Waltham residence with their throats slit and their bodies covered with marijuana. Tamerlan and Mess were once roommates and did boxing and martial arts training together.