(CN) - A federal jury found 21-year-old Robel Phillipos guilty Tuesday of lying to FBI agents investigating the Boston Marathon bombing.
Phillipos was convicted of two counts of lying to investigators after he was asked whether he had been in the University of Massachusetts-Dartmouth dorm room of suspected bomber Dzhokhar Tsarnaev when two other friends removed potential evidence.
Prosecutors said Phillipos and two other friends - Dias Azamat Tazhayakov and Dias Kadyrbayev - went to Tsarnaev's dorm room three days after the marathon bombing, and hours after the FBI announced Tsarnaev and his brother were the primary suspects in the bombing.
Kadyrbayev and Tazhayakov were convicted of removing a computer and backpack containing fireworks emptied of their powder. They await sentencing on obstruction of justice charges.
During the eight-day Phillipos trial, defense attorneys argued that their client did not intentionally lie to investigators. They said Phillipos could not accurately answer the questions put to him because he had smoked too much marijuana on the day he visited the dorm room.
Among those who testified on Phillipos' behalf during the trial was former Massachusetts Gov. Michael Dukakis, who said he was a longtime friend of the young man's family.
Phillipos, who will be sentenced Jan. 29, faces up to eight years in prison for each of the two counts. He will remain under house arrest and must wear a GPS bracelet until then.
U.S. Attorney Carmen Ortiz noted Phillipos "did just the opposite" as Americans rushed to help investigators in the aftermath of the bombing.
"He lied to agents when he could have helped," Ortiz said. "He concealed when he could have assisted."
Federal prosecutors say Dzhokhar and his older brother Tamerlan planted two homemade bombs near the finish line of the Boston Marathon. Three people were killed and more than 260 people were injured.
Dzhokhar Tsarnaev was arrested three days after the bombings after a massive manhunt that had the entire city of Boston on lockdown. Tamerlan was killed in a shootout with police.
Dzhokhar Tsarnaev has pleaded not guilty to more than two dozen federal charges. He is scheduled to go on trial next year.