A woman and three children — one boy and two girls — were found dead in a house on Eastmoor Drive in Grantsville, Utah on Friday night.
Police said the suspect was in custody after he showed up at an area hospital after the shooting.
Police have not identified the suspect or the victims but said the suspect showed up at the hospital with a fifth victim who was injured. They were driven there by a third person.
On Saturday morning, police were trying to piece together a timeline of events to determine what happened inside the house before the shooting took place, Grantsville Police Cpl. Rhonda Fields told 2News.
Fields said there were no known problems at the home — there was no history of calls to the house.
Officers were called to the scene after someone called 911 on Friday just after 7 p.m.
They found the four deceased victims in the house and later learned the suspect was at the hospital.
Fields said the suspect was arrested without incident.