A man allegedly gunned down his parents, his brother and his brother’s girlfriend in a domestic mass shooting at the family’s home in Michigan, according to authorities.

The shooting was reported in Livonia, about 20 miles outside of Detroit, at about 5:35 p.m. Tuesday, Livonia police said.

When officers arrived, the 25-year-old suspect walked out of the home with his hands raised and indicated “he had shot family members,” police said.

The suspect’s parents — 58-year-old Sterling Pierce and 53-year-old Holly Kimball — were found shot dead in the backyard, Livonia Police Chief Thomas Goralski said at a news conference Wednesday.

The suspect’s brother, 22-year-old Tanner Pierce, and Tanner Pierce’s girlfriend, 21-year-old Nevaeh Finch, were found fatally shot in a bedroom, Goralski said.

The parents and the brothers lived in the house and the girlfriend often stayed there, the chief said.

Goralski said there was apparently a “contentious relationship between the suspect and his parents,” but he added that police “don’t know what happened” and said investigators are still “working on motives.”

Police have not been to the house for any prior incidents involving the suspect, the chief noted.

The suspect, who was not named by police, was taken into custody, the chief said. There’s no threat to the public, police said.