PHILADELPHIA (AP) — The city issues demolition permits, but it isn't responsible for the work done by contractors on private property, Philadelphia officials said Wednesday at the first public hearing on this month's fatal building collapse.

The June 5 collapse at a downtown redevelopment site killed six people inside an adjacent thrift shop, and came after at least one citizen complaint that the demolition appeared unsafe.

Council members raised an array of concerns Wednesday, including the minimal requirements needed to get a demolition permit; the lack of urgency that followed the citizen's complaint; and the ever-changing mix of contractors, subcontractors and day workers found on job sites, despite permits that name only a developer or "expediter," an industry term for someone who pushes through the work and approvals.

City Controller Alan Butkovitz complained the city has long known its Department of Licenses and Inspections was understaffed and slow to respond to complaints, despite the fact that "what lies in the balance is human lives."

"It's a self-policing system. Or, you wait for something to happen," Butkovitz testified.

Deputy Mayor Everett Gillison promised that demolition permit requirements and oversight would be ramped up under an executive order Mayor Michael Nutter issued last week. But he warned that the city can't make the process so onerous that Philadelphia becomes "anti-development."

And, he added, "the public does not have liability nor responsibility" for the work done after a contractor obtains a permit to demolish private property.

Sean Benschop, a subcontractor, has been charged with involuntary manslaughter in the six deaths. Investigators said the ex-con was operating an excavator while high on drugs and improperly using the machine to knock down a four-story wall rather than doing the delicate work by hand.

Benschop was never named on the demolition permit, which was issued to expediter Plato Marinakos Jr., an architect working for developer Richard Basciano. Basciano, once dubbed the pornography king of Times Square, owned the three run-down storefronts being razed.

A grand jury is investigating whether anyone besides Benschop should be charged. And, for that reason, the testimony Wednesday was largely limited to questions about process and congratulatory plaudits for city workers, including building inspectors.

Williams called his inspectors, who must pass certification tests but do not need a college degree, "very well prepared."

"Our inspectors were trained based on what the (city) codes required. Ultimately, it is the contractors' responsibility to understand what is required, based on the code and building standards," said Williams, who took over the department last year.

An experienced department inspector, Ronald Wagenhoffer, visited Basciano's project on May 14, six days after the complaint came in, and deemed the concern unfounded. He had also done two routine site visits in February.

Wagenhoffer, 52, died of an apparent suicide last week. He left behind a videotaped cellphone message in which he faulted himself for not getting out of his truck and being more diligent. However, city officials said he also said, "It wasn't my fault."

The collapse killed two workers and four shoppers inside a Salvation Army thrift story, which was ground to rubble when the brick wall collapsed. Thirteen others were injured, some of whom have filed lawsuits.

"Someone shopping should have the expectation that they can safely do so without a calamity that took seven lives from us," said Councilman Curtis Jones Jr., who chaired the hearing.