At this point, it does not look like these suspects played a direct role in the attacks.
Two of the suspects, identified as Dias Kadyrbayev and Azamat Tazhayakov, came to the U.S. from Kazakhstan. Both are 19 years old and were charged with obstruction of justice for allegedly destroying or concealing a laptop computer and a backpack containing fireworks belonging to Dzhokhar. Both men have been held in jail for more than a week on allegations that they violated their student visas while attending UMass.
The third person taken into custody is U.S. citizen Robel Phillipos, 19, of Cambridge, Mass. He was charged with willfully making materially false statements to federal law enforcement officials during a terrorism investigation.
All three men were expected to appear in court Wednesday afternoon.
Authorities allege that on April 18, after the FBI released photos of the bombing suspects and the three men suspected their friend was one of them, they went to Dzhokhar Tsarnaev's dorm room. The men noticed a backpack containing fireworks, which had been opened and emptied of powder, the FBI said. Tazhayakov and Kadyrbayev allegedly agreed to throw the backpack in the garbage, but it was later found in a landfill by law enforcement officers.
Phillipos allegedly lied to investigators about visiting Dzhokhar's room. Prosecutors said he said he did not remember going to Dzhokhar's room, then said the three friends went there but did not go in. In his fourth interview with investigators, Phillipos "eventually confessed that he had lied to the agents," the court documents say.
If they are convicted, the two brothers from Kazakhstan could face up to five years in prison and Phillipos could face eight years.
The FBI investigation into the Boston attack has been expanding, and almost a dozen individuals are now considered to be persons of interest, according to ABC News.
The twin blasts at the Boston Marathon on April 15 killed three people and wounded 170 others. According to the FBI, about a month before the bombing, Dzhokhar Tsarnaev told Tazhayakov and Kadyrbayev that he knew how to make a bomb.
Brothers Tamerlan and Dzhokhar Tsarnaev were named suspects based on surveillance footage. Tamerlan was killed in a shootout with police days later, while Dzhokhar was captured alive following a massive manhunt.
It remains unclear what -- if any -- help the bombers had in building the devices themselves. Investigators are still looking into the possibility they received some help from terror groups overseas. Investigators have said that the older brother, Tamerlan, may have been in touch with suspected militants while in Russia last year.
The Associated Press contributed to this report.