Security cameras have recorded at least three nighttime instances where groups of people entered or exited sewer tunnels via maintenance holes on streets in Brooklyn and Queens.

In one video, taken early Friday morning in the Williamsburg section of Brooklyn, a group of roughly seven people were recorded popping out of a maintenance hole in the middle of an intersection, in full view of passing cars.

Some wore headlamps and carried what appeared to be shovels and other tools. One narrowly missed getting run over by a vehicle as they pulled themselves out of the ground.

In another video, a group of about seven people could be seen emerging from a maintenance hole around 2 a.m. on a quiet street in Brooklyn’s Gravesend neighborhood. They made their way to a couple of parked cars and pulled out fresh clothes to change into. Police say the group entered the sewers about 11 p.m., meaning they could have been underground for three hours.

On May 5, three people dressed in waterproof hip waders and other protective gear pried open a maintenance hole cover and descended into the sewer on a street in Queens. The last person pulled the cover shut as approaching cars slowed to a stop.

Aki Jakupovic, the owner of an auto detailing shop, said his shop’s surveillance cameras recorded that group of sewer spelunkers. He said he couldn’t venture a guess as to what the people did below ground but worried they were “up to no good.”

The city Department of Environmental Protection said it inspected the sewers at both Brooklyn locations and verified the sewer infrastructure wasn’t damaged. The incident in Queens is still under investigation, the agency said.

Rob Wolejsza, the department’s spokesperson, stressed that entering the sewers is not only illegal but “extremely dangerous.”

“Sewers can contain numerous hazards, including noxious and potentially deadly gases, unstable surfaces, flooding risks, and confined spaces,” Wolejsza said in a statement. “For these reasons, members of the public should never enter a pipe, drain, catch basin, manhole, or outfall.”

Last month, a woman fell into an open maintenance hole on a busy street in midtown Manhattan and died. Utility officials said the hole cover had been dislodged by a truck.

Police, meanwhile, said they don’t believe there’s any threat to public safety after conducting a thorough sweep of the areas. There have been no reports of injuries and no arrests, and the investigation is ongoing, the department said.

On Tuesday, at the busy intersection in Williamsburg where the second group was spotted, resident Anthony Purdie said he isn’t convinced it was simple curiosity that drew the group to explore the sewers in the cover of night.

“They look like they were looking for something important, like money, or for doing some type of hurting,” he said. “Ain’t no fun and games. I mean, seven grown adults going down there? Got to be something, man.”