Federal prosecutors have refuted claims they have a witness who could testify that suspected Boston Marathon bomber Dzhokhar Tsarnaev knew his older brother participated in a triple homicide in Waltham in 2011, as they sought to downplay the brother’s alleged role in the murders.
Lawyers for Tsarnaev cited the purported existence of the witness in court documents this month in arguing prosecutors are obligated to turn over evidence of Tamerlan Tsarnaev’s role in the Waltham killings.
Defense lawyers have sought to portray Tamerlan Tsarnaev as the dominating, persuasive older brother, and Dzhokhar Tsarnaev might have felt compelled to participate in the Marathon bombings out of fear.
“Such evidence would tend to corroborate Tamerlan’s dominant role in the charged offenses and would place the brothers’ respective personal characteristics and relative culpability into relief,” defense lawyers argued in the court documents.
But prosecutors argued in their own court filing Friday that the existence of such a witness was misstated in the defense team’s court filings.
“In fact, the government disclosed only that a third party had informed the government that there was someone who might say such a thing,” prosecutors wrote. “Whether that person would actually say it, let alone testify to it, is another matter entirely.”
The prosecutors did not say whether federal investigators have interviewed the witness, and what he or she said.
Tamerlan Tsarnaev’s alleged role in the Waltham killings has become a central theme in the defense of his younger brother. Brendan Mess, 25, of Waltham; Erik Weissman, 31, of Cambridge; and Raphael Teken, 37, of Cambridge, were discovered with their throats slashed in Mess’s apartment in a two-family house on Sept. 12, 2011. Marijuana was sprinkled on their bodies, and authorities presumed the killings to be drug-related. The murders were never solved.
The FBI disclosed that one of Tamerlan’s associates, Ibragim Todashev, confessed during an interrogation in Florida in May 2013 that he helped Tamerlan Tsarnaev commit the killings. Todashev was shot and killed by an FBI agent during the interrogation after he allegedly attacked the agent.
Lawyers for Tsarnaev have asked for more about the investigation into the killings, arguing in past court filings that the manner in which Tamerlan “induced Todashev to participate in the [murders] may shed light on the process by which he allegedly drew [Dzhokhar] into violence some 19 months later” at the Marathon. In a filing this month, the defense added, “even the government has conceded that evidence concerning Tamerlan’s participation in Waltham murders might be relevant if Dzhokhar Tsarnaev were aware of it.”
But government prosecutors argued in their reply that they cannot turn over information about the Waltham murders because the killings remain under investigation by the Middlesex district attorney’s office. Prosecutors say they have no evidence Tamerlan Tsarnaev was involved in the killings beyond Todashev’s confession.
The prosecutors also argue information about the killings is immaterial if defense attorneys seek to show Dzhokar Tsarnaev simply believed that his brother was involved.
“It makes no difference from a mitigation standpoint whether Tamerlan committed the murders or not, and the facts related to the murders would similarly be irrelevant,” the prosecutors argued.