Boston Marathon bombing suspect Dzhokhar Tsarnaev destroyed his mobile phone before being arrested, a lawyer for one of Tsarnaev's friends has said in court.
The information was disclosed on Monday during a pre-trial hearing in US District Court as lawyers for three of Tsarnaev's friends asked a judge to order prosecutors to turn over a variety of records and documents to the defence.
The defence requested all communications between Tsarnaev and the three men, as well as all communications between Tsarnaev and other people.
Authorities allege that the friends went to Tsarnaev's dorm room at the University of Massachusetts-Dartmouth several days after the bombings, soon after the FBI posted photographs of the two bombing suspects, Tsarnaev and his older brother.
Two of the friends, Dias Kadyrbayev and Azamat Tazhayakov, both Kazakhstan nationals, are charged with obstruction of justice and conspiracy for allegedly removing Tsarnaev's laptop computer and a backpack containing fireworks from his dorm room.
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Another friend, Robel Phillipos, is charged with lying to authorities while he was being questioned.
All three men have pleaded not guilty and their lawyers have said they had no prior knowledge of Tsarnaev's alleged involvement in the marathon bombing.
Robert Stahl, Kadyrbayev's lawyer, said prosecutors told defence lawyers that Tsarnaev destroyed his mobile phone before his arrest.
Stahl said that in other cases he's had, some text messages have been retrieved from mobile phones through a service provider. He asked Judge Douglas Woodlock to ask prosecutors to seek those text messages and turn them over to the defence.
Assistant US Attorney Stephanie Siegmann said prosecutors have already given the defence text messages between Tsarnaev and the three friends taken from the mobile phones of the friends.
"I believe the messages we've given them are all we could get," Siegmann told the judge.
Tsarnaev has pleaded not guilty to 30 federal charges in last year's marathon bombing. Authorities say he and his older brother built two pressure-cooker bombs and placed them near the finish line.
The blasts killed three people and injured more than 260.
