This shot is from one of the videos posted to YouTube. (CBC)

Police in Halifax are reviewing a series of YouTube videos showing women secretly filmed from behind as they walk around Dalhousie University.

University security staff sent an email to students Monday warning them to be alert. The university has asked Halifax Regional Police to investigate.

"The videos are disconcerting," Const. Brian Palmeter said in a statement Tuesday. "It appears that the video camera is obscured from sight, possibly in a kitbag."

The videos were posted by a user called LeggingSpy over the past three weeks. In most cases, the camera follows a young woman wearing yoga pants or leggings and zooms in on her behind. The women don't seem to know they're being filmed.

In two instances, Palmeter said, the camera seems to be aimed up a woman's skirt. "Certainly that's a little more invasive than the other videos," he told CBC News.

Charles Crosby, a university spokesman, said a staff member discovered the videos Monday and the email from security went out soon after.

Students told to be on alert

Security staff said the videos appear to have been shot around the Studley campus this fall.

"The nature of the video is an invasion of individual privacy, as well as being offensive in its content toward the subject of the recording," Mike Burns, director of security at Dalhousie, said in the email.

Dwight Fischer, the vice-president of information technology services at Dalhousie, said about 20 of the LeggingSpy videos appear to have been shot on the campus.

"They've crossed a line and it's totally inappropriate what they're doing with that equipment," he said Tuesday. "The biggest thing for us is we want to make sure that students always know what's happening around them, be aware, be more vigilant."

For one video on YouTube, the caption refers to the rear end of "a hot slutty college girl."

Palmeter said investigators are trying to track down the person who filmed the women and posted the videos and determine whether criminal charges are warranted.

Although the university is looking into whether it can get the videos removed from YouTube, at least one privacy lawyer in Halifax does not believe it can.

"If it's in a public place and it's publicly viewable, I don't think there'd be much chance of a prosecution, or even much chance of getting it removed from an online video-sharing site," said David Fraser, a lawyer at McInnes Cooper in Halifax.

The school wants to hear from anyone who suspects they were secretly recorded.