DULUTH, Minn. – A Minnesota man shot and killed his wife and son, and 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 just after 2 p.m. Thursday, 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.

Later Thursday, police identified Anthony Nephew as the suspect and surrounded his home. When they entered, officers found the bodies of him, his 45-year-old wife Kathryn Nephew, and their 7-year-old son, Oliver Nephew.

Police said Anthony Nephew apparently shot himself.

Duluth, a city of nearly 90,000 residents, is roughly 135 miles (217 kilometers) north of Minneapolis.