PHILADELPHIA (AP) - A veteran inspector who surveyed a downtown building weeks before it collapsed, killing six people, was found dead from a self-inflicted gunshot wound a week after the accident, authorities said on Thursday.

Mr Ronald Wagenhoffer, 52, was found shot in the chest in a truck on Wednesday night. A longtime employee with the Department of Licenses and Inspections, Mr Wagenhoffer had inspected the building May 14 and signed off on demolition work underway, after getting complaints about the site from the public, Deputy Mayor Everett Gillison said.

That was three weeks before the vacant four-story building collapsed onto a neighbouring Salvation Army thrift store on June 5, killing two employees and four customers and injuring 13 other people.

"With the building collapse a week ago, we have now lost seven lives in connection with this tragedy," Mr Gillison said at a news conference, adding that Mr Wagenhoffer leaves behind a wife and son. "This man did nothing wrong. The department did what it was supposed to do."

Department employees were informed of the death on Thursday morning. Mr Wagenhoffer was a 16-year city employee who had started with the Department of Public Property and worked his way up through the ranks to building inspector, according to city officials. He had worked until 3pm on Wednesday.

The department's head, Mr Carlton Williams, said Mr Wagenhoffer did everything he could to protect people.

"We strive to protect our citizens by enforcing the building codes. And that's what Ron did," Mr Williams said. "He was a dedicated civil servant who loved his job."

Investigators say a heavy equipment operator with a lengthy rap sheet was high on marijuana when the building collapsed. The operator, Mr Sean Benschop, faces six counts of involuntary manslaughter, 13 counts of recklessly endangering another person and one count of risking a catastrophe. His attorney has said he was being made a scapegoat.

The city's top prosecutor has convened a grand jury to investigate whether anyone else should face criminal charges. A half-dozen survivors have filed lawsuits against the contractor and the building's owner.

A demolition permit indicates that contractor Griffin Campbell was being paid US$10,000 (S$12,500) for the job. Mr Campbell's lawyer has called him despondent but "absolutely not responsible" for the deaths. On Thursday, he released a statement expressing condolences to the families of the inspector and the victims.