A city probe of a fatal crane collapse on a windy February morning in lower Manhattan found that the operator made a string of mistakes that led the crane to topple — including lowering the boom at an ­improper angle.

The Department of Buildings probe also found that crane operator Kevin Reilly — working for Galasso Trucking & Rigging — erred by not securing the boom the night before the collapse.

The collapse killed one pedestrian and injured three others, while damaging cars parked along Worth Street off Hudson Street.

Officials said they have suspended Reilly’s license and are seeking to have it permanently revoked.

Reilly’s lawyer, Stacey Richman, did not immediately respond to a request for comment.