Authorities are trying to figure out how a 91-year-old woman fell to her death at a long-term care facility in Montreal.

The incident happened Wednesday evening at the CHLSD de Louvain on St. Denis St. in Ahuntsic.

The facility says that staff members had just checked on the woman around 10:30 p.m., when they stepped out of the room for a few minutes.

When they returned the woman had fallen to her death.

Louise Mercier, a spokesperson for the facility, says she is certain the screens and windows were properly secured.

"We are certain that the windows were secure. I can confirm that," said Mercier.

"Yes, there is a screen, so people can open windows and get some air, etc.. but there is a special grate, bars that are very, very solid."

Mercier added that the windows were changed five years ago in order to be more secure.

At this point, the facility believes the frame around the screen might have failed. 

Health Minister Gaetan Barrette said it is too early to come to conclusions.

"I've not been informed of the physical details of that window and that institution. I'll wait for that information before I comment," said Barrette. 

Police, the coroner's office, and the public health board for the region are investigating the fall from the second-storey window.

They have already ruled out suicide and the possibility the woman was pushed.

Mercier said the woman arrived at the facility within the past two days, and they have had difficulty contacting her relatives because she has no immediate family.

Fatal falls from health care and long-term care facilities have happened before.

This past weekend a woman was injured falling out a window in Trois Rivieres.

Four years ago a patient fell to his death in St. Lambert soon after arriving at a health care facility.

That case convinced a coroner to order windows in Quebec care facilities be modified so that it is impossible to open them wide enough to fit through.