A city firefighter was arrested Thursday after he was caught on video stealing a bed cover from a parked pick-up truck in Queens while on duty — then using his FDNY truck to haul off the hot goods, according to police and surveillance footage.

Aleksander Sweiszek, 40, was charged with grand larceny and criminal possession of stolen property for stealing from a Dodge Ram that was parked on 56th Street and Northern boulevard in Woodside at 2:30 a.m. on Wednesday, police and sources said.

The 29-year-old owner of Exclusive Collision Repair on Northern Blvd, whose truck was stripped, recounted seeing the car pull up to his truck, which he had parked a few blocks over from his shop.

“I came yesterday to work… and when I got to the shop I noticed somebody had dismantled my truck,” he told the Post.

“I checked the cameras, and you saw, the camera says it all. An FDNY pick-up truck came out, casually driving and decided to take the bed cover off and put it in the FDNY truck.”

“I was like ‘What’s going on over here?’ I was shocked. I didn’t know what to say, I didn’t know what to do, I just thought ‘Oh, man. This is unbelievable.'”

Surveillance footage of the brazen theft shows the driver pulling up to the pick-up truck on the deserted street, hopping out, dismantling the truck’s bed cover and storing it in the FDNY van.

“There’s my truck with my ‘black bed guard’ and here comes the firemen [sic] to put out the fire… My God, it’s true,” the victim says in Spanish in the video, as Sweiszek casually steps out of the FDNY van and begins to take apart the bed cover.

“Look at him. And that weighs like 150 pounds. He took it. He robbed me. Look. FDNY,” he continues in Spanish. “FDNY! This is unf–king-believable. F-D-N-Y!”

“He took everything very casually,” the victim told the Post. “You know it’s crazy to see that – a New York City [employee] do something like that.”

“He got in and he got out!” he said, pointing out Sweiszek’s efficient performance – pulling off the theft in only 8 minutes. “That guy is good! I wish I got to know him, I would have given him a job at the shop,” the auto-body shop owner joked.

While reviewing the surveillance footage with the cops, he said he spotted the same FDNY pick-up truck driving past his car 30 minutes or so earlier.

“When this sort of thing happens, you expect an old customer, or a friend of yours, maybe an employee, you never know. But you’re never going to expect to see the FDNY doing some craziness like that!” the mechanic explained. “Like, come on, dude, what’s wrong with you!”

The bed cover was worth about $2,500, sources said, but the victim hasn’t heard anything about getting it back yet.

Sweiszek – who was assigned to Engine 206 in East Williamsburg – turned himself into the 114th Precinct on Wednesday afternoon and was issued a desk-appearance ticket police said. He was suspended without pay by the FDNY after his arrest.

“Craziness, bro. Craziness,” the mechanic says in the video.

Additional reporting by Jorge Fitz-Gibbon