An investigation into the fatal TriBeCa crane collapse last week has so far not uncovered any evidence of criminal conduct in the tragic sequence of events which brought the 565-foot long apparatus crashing down on to West Broadway and Worth Street, an official familiar with the probe said Tuesday.

Officials with the Manhattan District Attorney’s Office and the city Department of Investigation, two agencies which look for violations of criminal laws, are among those Mayor Bill de Blasio said would investigate.

Investigators are looking at whether winds, human error and mechanical failure — or combination of all three factors — contributed to the collapse of the crane while it was being lowered to a secure position in the face of rising wind gusts, a spokesman for the city Department of Buildings said. Officials have said that a computerized recording device — similar to an airliner’s black box — was being reviewed for clues.

But crane safety consultants who have viewed an amateur video of the crane toppling said possible human error, combined with gusting winds, may have been the major culprits. Stock market mathematician David Wichs, 38, died in the accident.

Terry Quirk a consultant and retired crane operator in Alaska, said in a telephone interview and follow-up email that the first thing he noticed in the video is that the “luffing jib,” the latticed boom which fell in a mangled red heap on Worth Street, was being lowered with its “headache ball,” a round object with a single cable and hook, still hanging high in the air off the jib. That was not done in accordance with standard procedure dictated by the crane manufacturer, he said.

Quirk said that he also noticed from the video that the main boom, closest to the cab, was being lowered before the luffing jib was firmly on the ground or in a vertical position.

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“This is not in accordance with the manufacturer’s procedures for raising or lowering a luffing jib,” said Quirk, adding that those two factors in his opinion constituted operator error.

“Kind of scary really,” Quirk said in an email.

Tom Barth of Barth Crane Consultants in South Carolina likened the weight stress to the difficulty someone would experience holding a bucket of water at arm’s length, instead of close to the body.

Quirk said the collapsed crane, owned by Bay Crane Co. of Long Island City, was a product of Liebherr Group, a well-known crane company based in Germany. A spokesman for the Department of Buildings said the crane was Liebherr’s model LR 1300.

De Blasio said the crane was being operated by Galasso Trucking and Rigging of Maspeth, Queens. Kevin Reilly of Port Washington was reportedly the crane operator. Officials at Bay Crane and Galasso Trucking have not returned repeated calls for comment. Reilly couldn’t be reached.

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Ron Brodek of Brodek Crane Inspections in Arizona, described as “a factor” wind gusts, which the National Weather Service said hit at least 26 mph at the time.