BOSTON (Reuters) - Defense attorneys for accused Boston Marathon bomber Dzhokhar Tsarnaev called on a federal judge late Monday to block law enforcement agents from monitoring jailhouse meetings between the suspect, his attorneys and his sisters.
Attorneys for Tsarnaev, who could be executed if convicted of killing three people and injuring 264 in the 2013 attack, argued there was no proof to support prosecutors' concerns that his sisters may be using "terrorist tradecraft" to pass messages to the surviving bomber.
"Raising such paper-thin concerns about security is a no-lose proposition for the government, because even the flimsiest of arguments, once ominously repeated and amplified by the news media, will inevitably tend to inflame the public's fear of the defendant," attorneys for the 20-year old ethnic Chechen said in a filing in U.S. District Court in Boston.
Defense attorneys are seeking to build a case that their client, the younger of the two brothers - who prosecutors say placed homemade pressure-cooker bombs at the race's crowded finish line and, three days later, shot dead a university police officer as they tried to flee the city - was less culpable than 26-year-old Tamerlan Tsarnaev.
The older sibling was killed after an exchange of gunfire with police during the brothers' attempt to escape.
The defense attorneys have argued that unmonitored meetings between the surviving Tsarnaev, his sisters and attorneys, would allow them to build a more comprehensive picture of his family dynamics. The assignment of a federal agent involved with the prosecution to monitor those meetings, they say, would interfere with their ability to develop that picture.
Prosecutors, who contend that Tsarnaev carried out the largest mass-casualty attack on U.S. soil since September 11, 2001, contend that failing to monitor those meetings would allow Tsarnaev's sisters to pass coded information to him.
"Only real time monitoring of social visitors' conversations with Tsarnaev by someone familiar generally with terrorist tradecraft and specifically with the facts of this case can ensure that those conversations are not being used as a vehicle to convey forbidding messages," they argued in a prior court filing.
(Reporting by Scott Malone; Editing by Bernadette Baum)