Tsarnaev allegedly knew brother was part of triple slaying

Tamerlan (left) and Dzhokhar TsarnaevAP/File

A prosecution witness could testify that Boston Marathon bombing suspect Dzhokhar Tsarnaev knew his older brother was involved in a triple homicide in Waltham in 2011, according to a defense motion filed in federal court Friday.

Prosecutors made the revelation of the existence of the witness in a letter in August, according to Friday’s filing, which asked for a variety of information from prosecutors, including legible copies of documents from the Russian government and information and evidence related to the Waltham killings. The case remains open, even after a friend of Tamerlan Tsarnaev reportedly confessed and implicated Tamerlan in the killings.

Defense lawyers for Tsarnaev asked that federal prosecutors be compelled to release evidence they called “critical to the defense case in mitigation.” Tsarnaev could face the death penalty if convicted for his alleged role in the bombings in April 2013 that killed three people and injured more than 260, and the killing of an MIT police office days later.

“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 stark relief,” Tsarnaev’s defense attorneys wrote in the filing.

Brendan Mess, 25, of Waltham; Erik Weissman, 31, of Cambridge; and Raphael Teken, 37, of Cambridge, were discovered dead in Mess’s apartment in a two-family house on Sept. 12, 2011. Their throats had been slashed and marijuana was sprinkled on the bodies.

Presumed to be a drug-related crime, the case went cold.

After the Marathon bombing, Tamerlan Tsarnaev emerged as a suspect in the killings, though the Middlesex district attorney’s office has remained tight-lipped about the case.

A spokesman for the office confirmed Saturday night that the investigation into the Waltham killings remains active and declined to comment for that reason.

Mayor Jeannette A. McCarthy of Waltham said Saturday she had yet to be briefed on any information related to the three-year old slayings.

“I have received no update,” she said in a phone interview Saturday night. McCarthy noted that typically, the chief of police provides her with information on crimes, she said.

It was unclear from the defense’s filing whether the prosecution witness has direct knowledge of the Waltham killings or would testify only to what Tsarnaev might have known about the crime.

A month after the Marathon bombing, Ibragim Todashev, 27, was fatally shot by an FBI agent in Florida after he allegedly confessed on tape to helping Tamerlan Tsarnaev kill the three men in Waltham. Tamerlan died in a confrontation with police four days after the bombings.

Friday’s filing was not the first time Tsarnaev’s defense sought evidence in the Waltham case.

In June, Tsarnaev’s attorneys asked the government for Todashev’s statements writing that the manner in which Tamerlan Tsarnaev “induced Todashev to participate in [the Waltham triple slaying] may shed light on the process by which he allegedly drew [Dzhokhar Tsarnaev] into violence some 19 months later” at the Marathon.

Prosecutors argued at the time that there was no relevant connection between the killings and the Marathon case and that revealing information to the defense could harm the homicide investigation.

“The Middlesex district attorney’s office is engaged in an active, ongoing investigation into the Waltham triple homicide,” prosecutors said at the time. “Disclosure of the details of that investigation could jeopardize it.”

In Friday’s filing, Tsarnaev’s defense team made the argument that the government had previously stated that any evidence related to the Waltham killings would only be relevant if Dzhokhar Tsarnaev was aware of his brother’s alleged involvement. The revelation by the prosecutors of the new witness would prove just that, the defense said.

“By letter dated August 15, 2014, the government disclosed that an identified witness would be prepared to testify that Dzhokhar had such awareness,” said the filing. “Thus, Tamerlan’s alleged role in the Waltham murders is now relevant even on the government’s crabbed reasoning.”

Brad Bailey, a Boston criminal defense lawyer, said the judge could rule that the evidence Tsarnaev’s attorneys are seeking is exculpatory, meaning that the defense is entitled to the information immediately, even if the Waltham investigation is not closed.

“It would suggest that Dzhokhar was afraid of his older brother or that his will was overborne out of fear of his older brother,” said Bailey. “They may be looking at terms in relevance for that.”

Lawyers representing Tsarnaev could not be reached for comment. The office of US Attorney Carmen M. Ortiz, and a spokesman for the Boston division of the FBI declined to comment on the filing.

The evidence linked to the Waltham killings was not the only information the defense requested. In the motion, Tsarnaev’s attorneys asked for documents and materials provided by the Russian government that were “cut off,” blank, or redacted, containing evidence of Tamerlan Tsarnaev’s radicalization as well as “his pre-existing intention to engage in violent jihad when he traveled to Russia in 2012.”

Requests were also made for transcipts and translations of phone calls Dzhokhar Tsarnaev made to his parents, reports of an examination performed on his computer, a list of digital devices the government plans on introducing into evidence, along with e-mails from Tsarnaev’s mother, Zubeidat Tsarnaeva.

Tsarnaev’s trial is scheduled to begin with jury selection on Jan. 5, 2015.