June 8, 2013— -- A excavator operator turned himself in today to face manslaughter and other charges in the collapse of a Philadelphia building that killed six people, police said.
Sean Benschop, 42, of Philadelphia, is going to be charged with six counts of involuntary manslaughter, 13 counts of recklessly endangering another person, one count of risking a catastrophe, Philadelphia Police Department Officer Jillian Russell said.
Marijuana was found in Benschop's system after the collapse, according to police sources.
The operator also admitted to taking codeine and other prescription drugs before the accident, and he was outfitted with a soft cast up to his elbow while working the heavy machinery, police sources told ABC News station WPVI-TV in Philadelphia. A source later confirmed the details to ABC News.
"Sean Benschop finally turned himself in to authorities today," Philadelphia Mayor Michael Nutter said. "It is because of his reckless and irresponsible behavior that six people died and 13 people were hurt and buried under debris and bricks.
"Our hearts are still hurting over the loss of those six good people, working or shopping at the Salvation Army Thrift Store, trying to 'do good,'" he said. "We continue to pray for the physical and mental recovery of the 13 survivors.
"It is my hope that the harshest level of charges are brought against Sean Benschop and he is punished accordingly," he said.
Nutter said investigators would also be looking whether the owners of the building shared any responsibility in the collapse.
"We must also seek answers from property owners Richard Basciano and Griffin T. Campbell who hired Benschop to do the significant job of operating heavy equipment," he said. "These three individuals bear the ultimate and sole responsibility for this tragedy. Justice will only be served if Sean Benschop receives a sentence that buries him in a jailhouse forever, just like his victims were buried on Wednesday."
Benschop declined to answer questions when a reporter with the Philadelphia Inquirer contacted him by cell phone Friday.
Citing court records, The Inquirer reported Benschop has been arrested 10 times for a range of offenses, including drug charges, theft, firearms and assault.
In addition to those killed, 14 more were injured when the vacant building collapsed on a Salvation Army Thrift Store Wednesday morning.
Rescue workers used buckets and their bare hands to move bricks and rubble to free a 61-year-old woman late Wednesday night, but that was the sole piece of good news to come from the pile of rubble where a four-story building used to stand in Philadelphia's Center City.
The 30-hour search-and-rescue operation for additional victims ended Thursday. At that time, Mayor Michael Nutter told ABC News that officials were confident there were no more people buried.
Those killed were identified as Kimberly Finnegan, Borbor Davis, Anne Bryan, Juanita Harmin, Mary Simpson and Roseline Conteh.
The building was being torn down as part of a community redevelopment project. The thrift store was open throughout the demolition.
Two of those killed were Salvation Army employees.
"We are deeply saddened by the tragic loss of life of the six individuals who perished in the wake of yesterday's building collapse," the organization said in a statement. "The passing of these individuals, including two of our employees, will be felt across our entire organization and throughout the community."
Philadelphia officials were facing tough questions over whether the accident could have been prevented.
Philadelphia Mayor Michael Nutter and the city's commissioner of licenses and inspections, Carlton Williams, have conceded that complaints about the working conditions at the demolition site were not followed up on.
City officials said that a routine inspection had found no violations at the property before demolition began. Williams said that inspectors had visited an adjoining property in May after complaints were lodged, but they found no violations and did not return to the Market Street site before Wednesday.
"No subsequent inspection occurred to indicate there was any unsafe conditions," Williams said. "We did not follow up and we are definitely looking into that."
Nutter promised a "wide-ranging investigation" into how and why the building collapsed.
In the wake of the collapse, Nutter has announced that every active demolition site in Philadelphia was being inspected for safety. He also announced a series of new rules for demolishing buildings within his city, including requiring a prohibition on using demolition machinery on a building if it is next to an occupied structure and mandatory drug tests and background checks for those operating heavy equipment on demolition sites.
At least 20 people were caught in falling debris when the building collapsed Wednesday around 10:45 a.m. An outer wall of the building that was being demolished fell outward and onto the two-story thrift store, according to city officials.
ABC News' Colleen Curry contributed to this report.