A crane operator who was working during the fatal Florida International University bridge collapse allegedly fled the scene — in his crane, according to a witness.

Carl Robertson dialed 911 after watching the horrific scene unfold March 15, when the 950-ton pedestrian bridge came crashing down, killing six people, the Miami Herald reported Monday.

But he also noticed something odd.

Just minutes after, he saw the crane’s operator jump out of the cab to untie caution tape police had strung before starting the machine and taking off down Tamiami Trail.

“He drove away in the crane and nobody stopped him,” said Robertson, who is homeless and resides near the site. “I didn’t think about it until later that day. I didn’t have my wits about me because they were pulling people out.”

Around the time of the crash, the giant white crane, which was rented from George’s Crane in Sweetwater, was lifting a piece of equipment to adjust the bridge’s internal steel supports, according to the Herald.

Photos and video taken just after the 1:47 p.m. collapse seem to corroborate Robertson’s claim: They show the crane situated on the bridge’s northwest side. But the rig is missing from a wide-frame shot taken by a Herald photographer about an hour later.

Using his outdated cellphone, Robertson was the first person to call 911, but he claims police never followed up with him.

Police said the unidentified crane operator drove the crane a short distance away afterward and stayed around, though it’s not clear for how long, the Herald said. They don’t appear to believe the man fled the scene or caused the collapse.

Bryant Blevins, a lawyer for George’s Crane, explained that the operator needed to move the rig out of the way to aid in the search and rescue. He drove it 30 blocks to the George’s Crane lot, but returned later that night to be interviewed by police and the Occupational Safety and Health Administration, the lawyer said.

“The emergency vehicles needed access,” Blevins told the Herald. “They were getting there pretty quickly after the collapse. At that point, he had to move the crane.”

Alan Goldfarb, an attorney representing the family of Alexa Duran, who was crushed to death in her car, questioned the crane operator’s actions.

“Why would he leave the scene?” Goldfarb wondered. “It doesn’t make any sense. How could you remove equipment from an investigative scene?”

The National Transportation Safety Board is investigating.

But independent engineers told the Herald that structural and design flaws caused the crash.