Bangladeshi police have arrested the engineer who warned that a building housing garment factories was unsafe a day before it collapsed.

Police official Ohiduzzaman said Abdur Razzak Khan worked as the Rana Plaza owner’s consultant when the owner illegally added three floors atop his five-story building.

Mr. Khan was arrested on Thursday on charge of negligence.

Police officials said that after pulling more bodies from the wreckage on Friday, the number of confirmed deaths stood at 501.