KADYRBAYEV, TAZHAYAKOV, and PHILLIPOS were each interviewed during this investigation. As set forth below, all three have admitted that on the evening of April 18, 2013, they removed Tsarnaev's backpack from Tsarnaev's dormitory room, and KADYRBAYEV and TAZHAYAKOV have admitted that they agreed to get rid of it after concluding from news reports that Tsarnaev was one of the Boston Marathon bombers. (my emphasis.)

There is no reference in the overt acts portion of the Indictment to their statements. Nor is Tsarnaev's roommate, who was at the dorm room when the three friends arrived to gather Jahar's things identified. (The roommate, as far as I know, has never been linked to any misconduct or involvement. He let the three friends into the dorm room and then left.)

The Government has to prove the two friends acted with the intent to impede the investigation. If Phillipos cooperates, perhaps the Government will rely on his testimony, along with the physical evidence retrieved from the landfill and phone records, to make the case, rather than their statements.

One more witness was taken into custody along with Kadyrbayev and Tazhayakov when police went to the Carriage Drive apartment. She was later identified by Azamat's father as Dias Kadyrbayev's girlfriend.

Here is a photo of Azamat Tazhayakov being taken in the first time. This is the second time.
Here is Dias Kadyrbayev the second time.