Boston police say three taken into custody in Marathon bomb case

BOSTON (REUTERS, AFP) - Investigators announced on Wednesday that they had arrested three more suspects as part of their investigation into the Boston marathon bomb attack that left three dead and more than 260 wounded.

"Three additional suspects taken into custody in Marathon bombing case. Details to follow," the Boston Police Department said on Twitter, later adding: "Please be advised there is no threat to the public."

The Boston Globe reported that three college students were arrested, and that they were arrested for "harbouring or aiding" two ethnic Chechen brothers whom investigators accused of placing pressure-cooker bombs near the Boston marathon's finish line on April 15.

One, Dzhokhar Tsarnaev, 19, is being held at a prison medical centre after being formally charged with crimes that carry the death penalty. His older brother, Tamerlan Tsarnaev, 26, died in a gunfight with police three days after the bombing that killed three people and injured 264 others.

CBS affliate WBZ-TV identified two of the suspects as Azamat Tazhayakov and Dias Kadyrbayev. Both are from Kazakhstan who appeared in court last week for a visa violation. The third suspect is said to be an unnamed American who will be charged with making a false statement.

Ms Linda Cristello, a Boston attorney who represented Tazhayakov and Kadyrbayev in immigration court on Wednesday morning, confirmed her clients now face separate federal charges and have an afternoon court appearance related to the bombing case.

The two have been held in jail for more than a week on allegations that they violated their student visas while attending the University of Massachusetts Dartmouth with Dzhokhar Tsarnaev.

The identity of the third suspect wasn't immediately released.

Reports from NBC suggested the three may have been arrested because they "helped take things out of Tsarnaev's dorm room after the bombings", but that there is "no evidence they particpated in planning" the attack.

A law enforcement source said Tazhayakov and Kadyrbayev may have thrown away a knapsack at Tsarnaev's request.

The US House of Representatives Homeland Security Committee, meanwhile, will hold a hearing on May 9 to examine the Boston bombings' impact on national security.

Boston Police Commissioner Edward Davis, Massachusetts Undersecretary for Homeland Security Director Kurt Schwartz and US Senator Joseph Lieberman have been asked to testify.

The committee will hold a series of hearings examining the events leading up to last month's attack, which killed three people and injured 264, as well as the reaction by law enforcement.

"Ultimately the investigation will assess how our efforts have evolved to meet the dynamic terrorist threat of foreign-inspired attacks on our soil, and what changes may be necessary to protect the homeland," committee chairman Michael McCaul said in a statement.