The FBI says there's no indication that the man who ambushed a Philadelphia policeman was part of an organized terror cell.

FBI Director James Comey (KOH'-mee) said at a news conference Thursday that the attack also didn't appear to involve a plot of violence beyond the Jan. 7 shooting that injured Officer Jesse Hartnett.

Police say Yeadon resident Edward Archer told them he was acting in the name of Islam when he opened fire on Hartnett's marked cruiser at an intersection.

Archer is charged with attempted murder but hasn't entered a plea. His mother says he had been hearing voices.

Police say Archer pledged allegiance to the Islamic State group.

A tipster told police that Archer was part of a group that included three others. Police had said they were not sure of its credibility.