MIDDLETON, Wis. (AP) — One person died when a house exploded in southern Wisconsin and authorities believe gunfire reported by neighbors happened when flames set off ammunition stored inside the home, police said.

Sheriff’s deputies and firefighters responded about 11 p.m. Tuesday after the house exploded just outside the city of Middleton, said Elise Schaffer, a spokesperson for the Dane County Sheriff’s Office.

One person was killed and the county medical examiner’s office is investigating, Schaffer said Wednesday.

Images posted by local media show the ruined home in flames after the explosion, which left a window and other debris scattered nearby.

The cause of the explosion remains under investigation, she said. Middleton is about 6 miles (10 kilometers) northwest of Madison.

Schaffer said she had no additional information to release Wednesday morning.

The sheriff’s office said in a news release that the fire “may have set off ammunition inside the home,” leading some nearby residents to report the sound of gunfire.