PHILADELPHIA — The city’s top prosecutor said Monday he would convene an investigating grand jury to look into a building collapse that killed six people and injured 13 others last week.
District Attorney Seth Williams said the ‘‘scope and depth’’ of the grand jury process will help prosecutors, the city, and others to ‘‘completely and appropriately investigate’’ what happened when a downtown building under demolition collapsed onto a neighboring Salvation Army Thrift Store, killing two employees and four customers.
‘‘I know Philadelphians demand action. I heard their voices loud and clear,’’ Williams said.
Police allege a heavy equipment operator, Sean Benschop, was high on marijuana when the collapse happened Wednesday. His attorney said it was an accident and his client is not responsible.
Benschop faces six counts of involuntary manslaughter, 13 counts of reckless endangerment, and one count of risking a catastrophe.
The grand jury will probably also ‘‘investigate the myriad municipal agencies and departments, and policies and protocols, surrounding the collapse,’’ Williams said.
Also Monday, the City Council announced the formation of a special committee to conduct a broad review of regulations regarding licenses and permits, construction and demolition, the certification of workers, and other issues.