New York City officials said workers have begun cutting a toppled crane into 35 pieces and trucking them off-site for forensic examination to determine what caused the towering structure to collapse along a city block in lower Manhattan, killing a pedestrian Friday morning.

Department of Buildings Commissioner Rick Chandler, speaking at a news conference Saturday, said the probe could take several weeks or longer. Officials have recovered an onboard computer that should reveal the angles of the 565-foot boom before it fell onto Worth Street, he said.

“It goes from A to Z,” Chandler said. “We’re going to look into the possible metal fatigue, make sure that the pins that are connecting pieces together, the counterweights, any wind information that’s possible, what loads were done even before, the previous day . . . The angles of the boom before it was moved, while it was moved. . . . The dunnage.”

Four cranes were on-site to help remove the fallen crane, a project officials expected to complete by Sunday morning, Chandler said. It could take longer for the street to reopen as officials inspect it and repair damaged pavement, he said.

A 73-year-old man who was hit with debris, one of three people hurt by the collapse, remained in stable condition Saturday at Bellevue Hospital Center in Manhattan, said Joseph Esposito, commissioner of the city’s Office of Emergency Management. The other two people injured were treated and released.

The crane’s operator passed drug and alcohol tests, Esposito said.

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Killed in the collapse was David Wichs, 38, a Harvard University-educated computer stock trader who worked on nearby Broadway at Tower Research Capital LLC, police said. Born in Prague, Wichs immigrated to the United States as a teenager, his sister-in-law Lisa Guttman said.

Workers were trying to lower the boom for safety in the wind and snow about 8:30 a.m. Friday when it collapsed into a mess of twisted red metal, crushing cars and damaging buildings about 10 blocks north of the World Trade Center.

City Comptroller Scott Stringer, hours after the crane collapse Friday, released a report criticizing the city’s response to what he called a “crisis” in crane safety. Of 65 crane safety recommendations outlined in a 2008 city study, the comptroller’s office said, Department of Buildings officials had fully implemented eight and partially implemented 17.

Esposito called the report flawed on Saturday, but did not elaborate.

“There’s a lot of inaccurate facts in that report, I must tell you,” Esposito said. “I don’t know where he got his information from. . . . We’ll deal with that at a later time.”

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With AP