Opening arguments are set to start Monday in a civil trial over a building collapse that killed six people and injured 13 others inside a Philadelphia thrift store.

The defendants include the owner and architect of a building that collapsed as it was being demolished and buried people in rubble inside the adjacent Salvation Army store.

The Salvation Army is also being sued for keeping the store open during the June 2013 demolition.

Two cut-rate contractors involved in the demolition are serving lengthy prison terms for involuntary manslaughter for failing to take an unstable brick wall down by hand and instead using heavy equipment.

New York-based building owner Richard Basciano and architect Platos Marinakos Jr. were never charged.

A gag order prevents lawyers involved from discussing the trial.