PERHAM (AP) -- A man charged with killing a woman and her adult son in Otter Tail County has been found incompetent to stand trial and will be committed to a secure treatment center in St. Peter.

Twenty-two-year-old William Hillman will be held at the center until his mental health improves and he's able to take part in legal proceedings against him.

Hillman is charged in the deaths of 42-year-old Denise McFadzen and 21-year-old Dalton McFadzen. They were found fatally beaten at their rural Perham home last April.

Authorities say Hillman was released from a mental health commitment in November 2017 after punching his mother and threatening to kill her. He moved in with the McFadzens about six weeks before they were killed.