New York City's police commissioner is calling Thursday's hatchet attack that wounded two officers an act of terrorism.
Commissioner William Bratton said a search of computers at the home of suspect Zale Thompson found Islamic extremist websites as well as articles about beheadings, the Canadian parliament shooting and White House intruders.
Police said Thompson had converted to Islam but probably acted on his own.
Thompson was swinging a hatchet when he rushed four policemen posing for a photographer on a street in New York's Queens neighborhood.
One officer was hit in the head and is in critical condition. Another was hit in the arm. Two others, who were not hurt, shot and killed Thompson.
