Surveillance video shows Azamat Tazhayakov taking a break during a four-and-a-half-hour interview with the FBI.
The special agent who conducted the sit-down told jurors Tazhayakov was cordial and answered all her questions, but said he would start shaking when talking about April 18.
That was the day he learned his college friend, Dzhokhar Tsarnaev, was a suspect in the Boston Marathon bombings.
The defense suggested in court that Tazhayakov was shaking because he didn't have a shirt and was cold. They've also suggested that the defendant was strong-armed by law enforcement.
Tazhayakov is accused of removing evidence from Tsarnaev's dorm room at the University of Massachusetts Dartmouth after the bombings. Some of those items include a backpack, laptop and fireworks.
Some of the families of the bombing victims were in court, including Paul Brown, the uncle of Paul and J.P. Norden.
Tazhayakov has not been not been charged in the attacks. The defense says he has cooperated with authorities and never even touched the Tsarnaev backpack with fireworks, pointing the finger at his roommate, Dias Kadyrbayev, who is facing similar charges.
Tsarnaev's college roommate testified in court that he did not even recognize Tazhayakov as one of the friends of the alleged bomber who came to his room on April 18.