A Florida Islamic group has filed a formal notice with the FBI that it plans to sue it for $30m (€26m) in the death of Ibragim Todashev, a friend of a Boston Marathon bomb suspect.

Boston Marathon bomb suspect Dzhokhar Tsarnaev’s lawyers may try to save him from the death penalty by arguing he fell under the murderous influence of his older brother, legal experts say.

Boston Marathon bomb suspect Tamerlan Tsarnaev took part in an earlier triple murder, according to a man subsequently shot dead while being questioned by authorities.

A Chechen immigrant shot dead in Florida after a confrontation with an FBI agent had ties to one of the Boston Marathon bombing suspects, and was being questioned at the time of the shooting.

A Chechen immigrant was shot to death by authorities while being questioned in the Boston Marathon bombing case yesterday after he lunged at an FBI agent with a knife, officials said.