A lawyer for a friend of the Boston Marathon bombing suspects says the charges his client faces are "unsubstantiated allegations."

The friend, 23-year-old Khairullozhon Matanov, of Quincy, is charged with obstructing the investigation into the deadly attack. He's accused of deleting information from his computer and lying to investigators.

Authorities say that in the days after last year's bombing, Matanov realized the FBI would want to talk with him because he knew the suspects and shared their "philosophical justification for violence."

Matanov was arrested Friday and appeared in court hours later. His lawyer, Edward Hayden, says his client didn't indent to mislead the FBI. He also says Matanov is "very frightened."

Matanov hasn't entered a plea. He is not charged with participating in the bombings or knowing about them in advance.