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

One person was found dead in the home's ruins after it exploded around 11 p.m. Tuesday just outside the city of Middleton, and a second body was found Wednesday afternoon, said Middleton Fire Chief Aaron Harris.

No additional people were at the home, but Harris said a dog that survived the explosion was found alive, checked out at an emergency veterinary clinic and determined to be in good shape.

Harris said the Dane County Medical Examiner’s Office would release the names of the two people following autopsies.

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

“The house was down immediately following the explosion and there was a large debris field,” Harris said. “There was a very large fire following the explosion.”

The cause of the explosion remains under investigation, said Harris and Elise Schaffer, a spokesperson for the Dane County Sheriff’s Office.

Harris said the home that exploded is in a rural area nearly 4 miles (6.4 kilometers) north of downtown Middleton. That city is about 6 miles (10 kilometers) northwest of Madison.

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.