Dias Kadyrbayev father
Amir Ismagulov, the father of Azamat Tazhayakov, visits the makeshift memorial for the victims of the Boston Marathon bombings in Boston, Massachusetts May 7, 2013. Azamat Tazhayakov and Dias Kadyrbayev, both from Kazakhstan, were charged by U.S. authorities on May 1 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 for Tamerlan and Dzhokhar Tsarnaev was under way.REUTERS/Brian Snyder

A friend of Boston Marathon bomber Dzhokhar Tsarnaev was sentenced to three-and-a-half years in US federal prison on 5 June, becoming the second friend of Tsarnaev to be sentenced for obstructing a federal investigation. A third friend is also scheduled to be sentenced later.

Azamat Tazhayakov, a Kazakh exchange student, removed a backpack containing fireworks from Tsarnaev's dorm room along with Robel Phillipos as police searched for Tsarnaev and his brother Tamerlan in a massive city-wide manhunt. Tazhayakov was convicted of obstruction of justice last year, Reuters reported.

"It just makes me sick what Dzhokhar did on April 15," Tazhayakov told the court, according to Reuters. "I didn't go there to the dorm room because I made connection that Dzhokhar was some jihadist. I never thought about it. At that moment I saw that one of my friends was alleged bomber and I didn't know if it was true or not."

Tazhayakov told federal Judge Douglas Woodlock that he regretted his actions, the Wall Street Journal reported. "And not just because I'm in jail but because I know I could have made better decisions. I could have called police," he said. "I apologise to the city of Boston for what I did."

Woodlock agreed with Tazhayakov's attorney that he had played a lesser role in the bombing's aftermath but that "he had the opportunity to do the right thing and he didn't."

According to Reuters, prosecutors had sought a four-year sentence for Tazhayakov, citing his willingness to testify against his friend.

Other friends jailed

Another Kazakh exchange student, who was also friends with Tsarnaev, was sentenced on 2 June after pleading guilty to obstructing the investigation into the marathon bombing that killed three and injured over 260. Dias Kadyrbayev was sentenced to six years in federal prison.

Investigators revealed Kadyrbayev tossed Tsarnaev's backpack into a dumpster near the apartment he shared with Tazhayakov.

Cambridge-native Phillipos was found guilty of lying to investigators in October and is scheduled to be sentenced later on Friday. Reuters reported that former Massachusetts Governor Michael Dukakis, who is friends with the Phillipos family, urged a lenient sentencing for Phillipos. "I can't understand why justice would be served by incarcerating him," Dukakis said.

Neither of the three young men is believed to have had any advanced knowledge of the terror attack.

Tsarnaev, who was sentenced to death in May, will be formally handed down his sentence in late June.