A friend of Boston Marathon bombing suspect Dzhokhar Tsarnaev was convicted Tuesday of lying during the investigation into the 2013 attack.

Robel Phillipos, 21, of Cambridge, was convicted of two counts for lying about being in Tsarnaev's dorm room while two other friends removed a backpack containing fireworks and other potential evidence three days after the bombing while an intense manhunt was underway for the suspected bombers.

FBI agents testified that Phillipos told them a string of lies about the night of April 18, 2013, before finally acknowledging he had been in Tsarnaev's room at the University of Massachusetts-Dartmouth with the two men who removed Tsarnaev's backpack and computer.

Phillipos' lawyers said he was a frightened 19-year-old who was intimidated by the FBI and too high on marijuana to clearly remember what he did that night. The defense called several friends who said Phillipos smoked marijuana a half-dozen times that day.

The defense also called former Massachusetts governor and 1988 Democratic presidential nominee Michael Dukakis to testify for Phillipos. Dukakis, an old family friend of Phillipos' mother, described a phone conversation he had with Phillipos five days after the bombings. Dukakis said Phillipos told him he had been questioned by the FBI for five hours, but was so confused he didn't remember what he said.

The defense also claimed that Phillipos' confession was coerced by FBI agents.

Prosecutors scoffed at Phillipos' marijuana defense, telling the jury that he was able to remember many details about April 18 and lied about his activities that night because he knew he had done something wrong.

The two friends who removed Tsarnaev's backpack were both convicted of conspiracy and obstruction of justice.

Tsarnaev is awaiting trial in the bombings. He has pleaded not guilty to 30 federal charges and could face the death penalty if convicted.