U.S. authorities on Wednesday (May 1) charged three men with interfering with the investigation of the Boston Marathon bombing, saying they hid fireworks and a backpack belonging to one of the suspected bombers as a manhunt was under way.

The three, two students from Kazakhstan and a U.S. citizen, were described as friends of surviving bombing suspect Dzhokhar Tsarnaev, 19. They were not charged with direct involvement in the April 15 marathon bombings, which killed three people and injured 264.

But three days after the blasts, the trio moved swiftly to cover up for their friend when the FBI made public pictures of the suspected bombers, made a public plea for help locating them and conducted a day-long manhunt that left much of Boston on lockdown, according to court papers.

Authorities charged the two Kazakhs, Azamat Tazhayakov and Dias Kadyrbayev, both 19, with conspiring to obstruct justice by disposing of a backpack containing fireworks they found in Tsarnaev's dorm room. The third man, Robel Phillipos, also 19, was charged with making false statements to investigators.

Kadyrbayev and Tazhayakov face a maximum sentence of five years in prison and $250,000 fine. Phillipos faces a maximum sentence of eight years in prison and a $250,000 fine.

None of the suspects addressed the court, other than to respond to the judge's questions. U.S. Magistrate Judge Marianne Bowler reprimanded Phillipos for not seeming to pay attention to the proceedings.

"I suggest you pay attention to me rather than looking down," Bowler said.

Kadyrbayev's lawyer, Robert Stahl, said before the hearing that his client was "not a target" of the bombing investigation, but declined to comment on any other specifics. He said his client had "cooperated fully" with investigators and "wants to go home to Kazakhstan."

Tazhayakov told the FBI, according to reports, that a month prior to the bombings, Dzhokhar Tsarnaev had told him over a meal that he knew how make a bomb.

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