DULUTH, Minn. (AP) — A Minnesota man shot his wife and son, as well as his ex-partner and their son, before killing himself, authorities said Friday.

Duluth police have not determined a motive, but Police Chief Mike Ceynowa said at a news conference that the shooter, 46-year-old Anthony Nephew, had “a pattern of mental health issues.”

Officers were first called to a home Thursday after 2 p.m., police said. They found Erin Abramson, 47, and Jacob Nephew, 15, dead from apparent gunshot wounds. Abramson and Anthony Nephew were previously involved in a relationship, Ceynowa said.