MONTREAL — Montreal police are investigating after a bystander said she saw two officers having sex with two women in a cop cruiser.

Police say they'll discipline at least one officer after a photograph showed a constable with a half-naked woman inside the marked car.

The photo, which was making the rounds on the Internet this week, shows a man in uniform sitting in the driver's seat with a topless blonde woman on his lap.

Leila Saad, who took the photo, told QMI Agency that there were, in fact, two officers in the cruiser, each having sex with a woman.

Saad said she was with friends when they approached the vehicle and snapped the photo.

"At first we thought it was a joke," said Saad. "(Then) we clearly saw the two policemen and two girls and what they were doing."

A video clip was also released Wednesday shows two officers standing near a cruiser with a blonde woman and a dark-haired woman.

Montreal police confirm that a six-year veteran of the force will face disciplinary action.

"At first we doubted it — we thought it was edited," spokesman Ian Lafreniere said of the photo.

"But when we heard the testimony of the person who took the photo, we were able to move the investigation forward."

Lafreniere wouldn't say if the officer in the photo was having intercourse with the woman, but he spoke of "inappropriate acts" that could lead to a suspension.

He confirms a second officer is also being questioned and could also face sanctions.

- With files from Valerie Gonthier