Montreal residents are demanding to know why a police officer was seen sitting parked in an alleyway in his patrol car with a woman on his lap.

The officer involved is now facing disciplinary action after a photo of the incident was uploaded to Facebook and circulated on Twitter.

Passerby Leila Saad snapped the pic Sunday night, after she noticed a police officer, parked in an alley near Ste. Catherine Street, ignoring a vehicle driving the wrong way down the lane.

She saw that the patrol car’s interior light was on, and then spotted a bare-shouldered woman sitting on the officer’s lap.

Saad says it was obvious to her that the two were having sex. She says there was also another woman with a police officer in the back seat, which she found strange.

“Why they have police with two girls in the car? It's weird,” she told CTV Montreal.

As soon as the vehicle’s occupants noticed they were being watched, they got out of the vehicle, Saad recalled.

After the 19-year-old posted her photo of the scene on Facebook Monday morning, the image spread like wildfire. But she adds it wasn’t long before she also started getting threats from people who were angry she posted the shot at all.

Saad says she’s nevertheless glad she took the photo and shared it.

“In a sense, I’m proud of this because you can see what police officers are doing. A lot of people think that police officers are good people, but you can see that sometimes, they’re not using their heads,” she said.

Montreal Police spokesman Cmdr. Ian Lafreniere says when officers first saw the grainy photo, they suspected it was fake. But when another witness came forward reporting the same incident, police decided to investigate.

The second witness had noted the identifying number on the patrol car, making it simple to track down the officer involved.

Lafreniere insists the woman involved in the incident was not naked and there was no sexual act taking place. He added it was unclear who the woman or women involved were or how she or they found themselves inside the patrol car.

“What was the link? What happened exactly? We’ve got no victim at this moment. No one has reported this. It’s only the witness that has come forward,” he said.

He added the investigation is still trying to determine where the officer's partner was but that so far, only one officer is facing discipline.

That discipline could include a suspension from duty. The officer is currently been pulled out of duty but has not been formally suspended.

"We take this seriously," Lafreniere told The Canadian Press. "A lot of police officers are not happy now because it's extremely bad for their job, their professionalism. This is not all the force. This is not the way officers are working in Montreal. This is one case."

With reports from CTV Montreal’s Natalie Nanowski and The Canadian Press