Boston Marathon bombing: Three college friends of Dzhokhar Tsarnaev charged with interfering in investigation as it emerges one did not hold a valid US visa

Two men charged with conspiracy to obstruct justice, the third with making false statements to investigators

Bill Iffrig, 78, lies on the ground as police officers react to a second explosion at the finish line of the Boston Marathon (AP Photo/The Boston Globe, John Tlumacki)

Three college friends of 19 year old Dzhokhar Tsarnaev, the surviving Boston marathon bombing suspect, have been charged with interfering with the investigation following the attack.

Azamat Tazhayakov and Dias Kadyrbayev, both students from Kazakhstan, have been charged with conspiracy to obstruct justice by throwing away a backpack containing fireworks and a laptop computer belonging to Dzhokhar, who is accused to planting the bombs near the marathon finish line on 15 April with his elder brother Tamerlan. A third man, an American citizen named Robel Phillipos, has been charged with lying to investigators.

It has emerged that Tazhayakov was allowed to return to the US from Kazakhstan in January despite not having a valid student visa.

The government acknowledged that US Customs and Border Protection was unaware that the student was no longer in college when he was let back into the US.

The disclosure was another instance of possible lapses by the government in the months before the bombings.

Dzhokhar was captured on 19 April and has since been charged with using a weapon of mass destruction for his role in the marathon attack. 26-year-old Tamerlan was killed during a police shootout in the early hours of 19 April.

The three men charged earlier today attended the University of Massachusetts at Dartmouth, the college where Dzhokhar was a student. Mr Tazhayakov and Mr Kadyrbayev were already facing accusations of having overstayed their student visas, and had appeared in immigration court hours before the charges related to the bombing investigation were announced.

If convicted, the two Kazakhs face up to five years in jail, along with fines of $250,000, while Mr Phillipos faces a maximum jail term of eight years. Mr Phillipos also faces a possible $250,000 fine.

According to court documents, the three have admitted to removing Dzhokhar's backpack from his room at the university on 18 April, the same day that FBI investigators released images showing Dzhokhar and Tamerlan near the marathon finish line shortly before the two explosions. They had not been identified at the time.

The criminal complaint recounts how Dias Kadyrbayev texted Dzhokhar after thinking that one of the suspects in the FBI images looked like him. Tsarnaev is said to have responded with texts containing “lol” and “you better not text me” and “come to my room and take whatever you want.”