The cause of the fire at Hulen Mall was still being investigated Sunday as the mall prepared to reopen. The fire in Fort Worth on Friday evening was first reported as a building and a roof collapse but was upgraded to a two-alarm blaze, firefighters said.

A day after a rooftop fire sent shoppers fleeing from Hulen Mall, investigators are still working to determine what sparked the blaze. The fire broke out Friday evening between Macy’s and Red Robin, where roof construction was underway.