Numerous onlookers at the site of the deadly collapse claimed they had long been troubled by the quality of the demolition work, which appeared to some to be unsafe.
City officials were quick to note that Campbell, 49, is a licensed contractor, but records paint a picture of a guy with a checkered past.
In 2011, the District Attorney's Office attempted to have a property that Campbell owned at 1339 Pike St. transferred to its custody through Common Pleas Court.
Officials alleged that the property was "being used to commit and/or facilitate violations of the Controlled Substance, Drug, Device and Cosmetic Act of 1972," according to court records.
Campbell contended that he didn't know about or consent to the activities that occurred in the property. He agreed to sell it within six months, or else face having it forfeited to the D.A.'s office.
City records show that Campbell still owns the property - and owes $3,975 in back taxes.
He pleaded guilty in 2009 to insurance fraud and criminal conspiracy. Campbell was sentenced to four years' probation and ordered to pay $10,700 in restitution, court records show.
In January, the city issued Campbell a contractor's license.
Two months later, he filed for Chapter 13 bankruptcy protection in the U.S. Bankruptcy Court Eastern District of Pennsylvania, listing $100,000 to $500,000 in business-related debts, according to court records.
Campbell had no trouble finding demolition work in between, however.
In February, his company was issued permits to do demolition work at 2136-38 Market, as well as properties at 2134 and 2132 Market.
The city said all of those properties are connected to STB Investments, which counts infamous Times Square porn king Richard Basciano as one of its members.
Deputy Mayor Alan Greenberger said Basciano, 87, had indicated that the demolition work - which cleared away Les Gals and the Book Bin II, two porn landmarks in the same block as the Salvation Army shop - was "part of a larger land assembly that he was putting together, with the intention of wanting to do some kind of development."
So how did Campbell get the permits to do the Market Street demolition work?
Plato Marinakos, the chief executive of Plato Studio, got them for him.
Marinakos, who is listed on Licenses & Inspections documents as the demolition contractor for the 2136-38 Market St. project, said by phone yesterday that he had served as an "expediter" to help get the L&I demolition permit.
Preston Moritz, a spokesman for Marinakos, said later that Campbell's company had approached Marinakos to assist in the L&I permit process, but that Marinakos hadn't approved the demolition plan and wasn't overseeing the work.
"It's Griffin Campbell that is responsible for the permit. They take ownership of the permit once it's expedited. They are responsible for the work," Moritz said. "Plato doesn't look at the plans."
L&I spokeswoman Maura Kennedy said Marinakos's involvement as an expediter "doesn't raise any issues."
Records show that Marinakos had pulled permits for at least five other properties that Campbell's company worked on, four of which were demolition jobs.
Campbell could not be reached for comment, and no one answered the door at the Nicetown rowhouse that's listed as his business address.
Amala Chisolm, who identified herself as Campbell's mother, said she learned of the building collapse from a neighbor.
She described her son as a hard worker "ever since he was able to talk" and said he's worked in construction for years.
"I'm glad my son is OK, and I think his crew is OK," Chisolm said, while sitting on the front porch of a house that Campbell owns on Pike Street in Hunting Park. "Everyone needs to pray."
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