The owner, property manager, and architect whose Center City demolition project ended in the deadly 2013 collapse that crushed a Salvation Army thrift store failed to follow construction industry "customs and practices" in hiring their demolition contractor, an industry expert testified Thursday.

The result, Stephen A. Estrin told a Philadelphia jury, was the hiring of a novice demolition contractor who was "totally incompetent and inexperienced."

Estrin testified for the plaintiffs in the Common Pleas Court trial of lawsuits filed on behalf of six people killed and 13 injured on June 5, 2013.

Estrin said Richard Basciano, the New York real estate speculator who owned the vacant four-story Hoagie City building at 2136-38 Market St., and his property manager and top aide, Thomas Simmonds, did no due-diligence research before hiring North Philadelphia demolition contractor Griffin Campbell.

Instead, Estrin said, Basciano and Simmonds relied solely on a recommendation by Center City architect Plato A. Marinakos Jr., whom they hired as their representative monitoring demolition of five Basciano properties in the 2100 and 2200 blocks of Market Street.

And Marinakos recommended Campbell, the lower bidder against two established demolition contractors, despite the fact that Campbell had no city contractor's license and had demolished just two burned-out rowhouses.

Estrin, 77, of Osprey, Fla., is a former carpenter and general contractor who for the last eight years has worked as a "forensic construction consultant" analyzing building failures.

Estrin has worked for about 25 years with Robert J. Mongeluzzi, one of the chief plaintiff's lawyers in the collapse. Mongeluzzi used Estrin as an expert in litigation involving the 2000 Pier 34 collapse on the Delaware River, which killed three people and injured 43.

On Thursday, Mongeluzzi projected on a courtroom screen quotes from deposition testimony of Basciano, Simmonds, and Marinakos.

Then, over repeated defense objections overruled by Common Pleas Court Judge M. Teresa Sarmina, Mongeluzzi asked Estrin for his opinion on whether their actions complied with industry standards.

Basciano and Simmonds testified that they knew nothing about Campbell before Basciano approved and Simmonds signed the contract with him.

"I'm responsible for everything he does," Estrin said, describing the legal relationship between an owner and a contractor the owner hires.

According to earlier testimony, Marinakos recommended Campbell - with whom he had worked on several small projects - for the Basciano demolitions despite knowing that Campbell was unlicensed, did not have insurance coverage for demolition, had not formed a company or opened a corporate bank account, and cashed his $25,000 deposit from Basciano's STB Investments Corp. at a local check-cashing agency.

"Demolition work is too dangerous to have someone doing for the first time," said Estrin, who is to continue testifying Friday.

Campbell had successfully razed two adjacent Basciano buildings in the 2100 block of Market before getting to the Hoagie City building in February 2013.

On the morning of June 5, 2013, as an excavator operator Campbell hired picked at the rear of the building, a three- to four-story unbraced brick wall toppled and crushed the one-story thrift store.

Six people died in the rubble, and 13 were injured. One of the injured died 23 days later.

Being sued are: the Salvation Army, Basciano, STB, Marinakos, Campbell, and excavator operator Sean Benschop.

215-854-2985 @joeslobo