Philadelphia DA says grand jury will be convened to probe building collapse that killed 6

PHILADELPHIA – Prosecutors in Philadelphia say a grand jury will be convened to investigate a building collapse that killed six people.

District Attorney Seth Williams said Monday that the "scope and depth" of the grand jury process will help prosecutors, the city and others to "completely and appropriately investigate" the collapse that also left 13 people injured.

The downtown building was being demolished when it collapsed onto a neighboring Salvation Army Thrift Store on Wednesday, killing two employees and four customers.

Police allege a heavy equipment operator was high on marijuana when the collapse happened. He surrendered Saturday to face charges in the deaths.