Dias Kadyrbayev and Azamat Tazhayakov, two college friends of Boston Marathon bombing suspect Dzhokhar Tsarnaev, pleaded not guilty on Tuesday to charges that they interfered with the bombing investigation. Both 19-year-olds are accused of removing a laptop and a backpack from Tsarnaev's dorm room after they learned that he was a suspect, then disposing of the backpack in a garbage bin outside their apartment. According to the indictment, the backpack contained fireworks (manipulated so that the explosive powder was exposed) and Vaseline, which Kadyrbayev allegedly thought was an ingredient for a homemade bomb. Family and supporters of both men were present in the courtroom. “If he wanted to assist in terrorism, he would have hid the computer,” Tazhayakov’s father, Arkady Bukh, said via his attorney, adding that he gave the computer to investigators immediately after they asked for it.