OTTAWA — Sudden deaths in La Loche, Saskatchewan, where shootings at two locations left four people dead and seven wounded on Friday, are an all too familiar event. But before Friday, suicide was the main cause of such deaths.

The police on Saturday offered few additional details about the shootings. The 17-year-old suspect, whose motive has not been revealed, remains in the custody of the Royal Canadian Mounted Police, who said they had also seized a weapon. The police said the suspect, whose identity cannot be disclosed because of his age, faced four charges of first-degree murder, seven charges of attempted murder and a weapons charge.

The police identified the victims as Marie Janvier, 21, an educational assistant at the school, Adam Wood, 35, a teacher who moved to La Loche from Ontario in September, and two brothers, Dayne Fontaine, 17, and Drayden Fontaine, 13, who were killed at a home about half a mile from the school.

La Loche is more than seven hours northwest of the nearest major city, Saskatoon. It is a community with high levels of unemployment and addiction to drugs and alcohol and a reputation as a tough town. In 2011, two Mounties were forced to barricade themselves into the local health clinic when a mob attacked them after incorrectly assuming that the officers had beaten a man who had been injured in an all-terrain vehicle accident. A police truck was also burned, and an ambulance badly damaged. When La Loche appears in the provincial news media, it is usually in connection with violence or drug arrests.

But looming over the town, whose residents are predominately Dene Indians, are sporadic waves of suicides, including one last year. Eighteen people, most of them young, killed themselves from August 2005 to January 2010 in La Loche, which has a population of about 2,600.