Hélène Monast was an 18-year-old from Chambly, Quebec, killed on the night of September 10, 1977, the day she celebrated her birthday. She spent the day with family, went out that evening with a friend, and was last seen leaving her friend near the Motel Mon Repos area. Around 11:15 p.m. she walked alone toward her godmother’s home on rue Migneault; investigators place the attack at roughly 11:30 p.m. in the Parc des Ateliers beside the Chambly Canal.

Her body was discovered the next morning close to where she had been walking. The autopsy found asphyxia by strangulation and recorded facial bruising, neck injuries from violent pressure, and bite marks on a breast. Some clothing and effects were reported at the scene, but her burgundy shoulder purse was never recovered. The coroner did not find physical evidence of violence to the external genital area.

Chambly police and the Sûreté du Québec handled the initial inquiry. Over the decades questions have arisen about scene control and the availability of physical exhibits; some items were later destroyed or became unavailable. No arrest was announced, and the case remained unsolved as investigators and Hélène’s family sought new leads, including renewed publicity in 2015 and a case review in 2024.

Did anyone in Chambly that night see Hélène with an unidentified man or notice a burgundy shoulder purse that might help explain what happened?