Fire ripped through four rowhomes in York today, displacing nine people and causing $100,000 damage. Acting Chief David Michaels now says it was an arson. It started around 11am at 356-358 Oak Lane in the city. Witnesses told FOX43 News it may have been started by kids playing with matches who then set a mattress on fire in a small breezeway between two of the homes. One witness saw the teens run from the breezeway laughing just prior to the fire.