It happened around 3 a.m. Sunday at a house south of Earlville on Co. Highway 1.
Two unidentified people went into the house. Then the homeowner shot one of them.
They were taken to the hospital in Mendota, where they were pronounced dead.
The second intruder drove off, but police later arrested them.
Multiple agencies are investigating to determine the identity of the shooting victim and the person in custody.