MONTREAL -- Longueuil police on Monday set up a command post in an effort to find out how a woman received a severe head injury last week.

The police force received a 911 call on Jan. 27, in the evening. A woman had left her home on foot and was found suffering from a head injury. Officers suspect a criminal act. They later found the woman near the corner of Marie-Victorin Boulevard and Charbonneau Street, in Longueuil.

The force is hoping witnesses will come forward and noted that people who want to do so anonymously could call (450) 463-7211. Anyone who drove near the area between 10:30 p.m. and 11:15 p.m. on Monday may have information. No detail is considered too small.

The command post will be set up from 5 p.m. until 1 a.m. at the corner of Marie-Victorin Boulevard and Charbonneau Street, in Longueuil, the police force wrote in a press release.