In this undated photo released by the U.S. Attorney's Office and presented as evidence during the trial of Azamat Tazhayakov in U.S. District Court in Boston, name tags are affixed to the former dorm room door of Boston Marathon bombing suspect Dzhokhar Tsarnaev at the University of Massachusetts-Dartmouth. Tazhayakov, a friend of Tsarnaev, is on trial on obstruction of justice charges, accused with another friend of removing items from Tsarnaev's dorm room. He is not charged with participating in the bombing or knowing about it in advance. (AP Photo/U.S. Attorney's Office)

Boston - The trial of a friend of the accused Boston Marathon bomber on Thursday is expected to turn to evidence of text messages between the defendant, a Kazakh exchange student, and the man accused of the deadly 2013 blasts.

Azamat Tazhayakov is the first of three friends of Dzhokhar Tsarnaev to face trial on charges of obstructing the investigation into the bombing by removing a laptop and backpack containing empty fireworks shells from the suspected bomber's dorm room three days after the blasts.

Attorneys for Tazhayakov, 20, argued at the start of the trial earlier this week that he never touched the items, but that his friend Dias Kadyrbayev, also 20 and from Kazakhstan, removed both from Tsarnaev's room at the University of Massachusetts Dartmouth and later threw the backpack into a dumpster.

On Wednesday, prosecutors played a video deposition from Kadyrbayev's girlfriend in which she said she had urged him to dispose of the backpack.

An FBI agent who specializes in electronic searches, James Scripture, is expected to return to the witness stand at the U.S. District Court in Boston on Thursday for the fourth day of the trial, which is expected to run two to three weeks.

Tazhayakov could face up to 25 years in prison if convicted of obstruction of justice and conspiracy. Kadyrbayev faces the same charges.

A third man, Robel Phillipos of Cambridge, Massachusetts, is accused of the lesser charge of lying to investigators.

Trials for Kadyrbayev and Phillipos are scheduled for later this year.

Tsarnaev is awaiting his trial, set for November, on charges that carry the death penalty if convicted.