Investigators are still trying to figure out the cause of a 4-alarm fire that tore through several buildings in Old City over the weekend.
It happened at 3rd and Chestnut Streets early Sunday morning.
The Bureau of Alcohol, Tobacco, Firearms and Explosives is now involved in that investigation.
Officials still have a collapse zone set up around those buildings.
Investigators say that several pets died in that fire.
The Red Cross is helping more than 100 people that were displaced.