ALEXANDRIA (AP) - The father of a man who authorities say shot a sheriff's deputy in Minnesota before killing his girlfriend and then himself was likely motivated by a child custody dispute.

Jeff Blowers says his son, Devin Blowers, was distraught because child welfare officials in Fargo, N.D., wouldn't let his son and girlfriend Katie Ray Christopherson have custody of their baby girl.

Blowers says his son has a history of drug problems and met Christopherson at a Fargo rehabilitation center last year. He says the couple's daughter was born three months prematurely Jan. 13 and remains in a Fargo hospital.

Authorities say the 24-year-old Blowers shot Douglas County Sheriff's Deputy Dustin Alexander at a farm in west-central Minnesota Monday. The deputy was wearing a bullet-resistant vest and is recovering. Officials Blowers then fatally shot Christopherson and himself.