Editor’s Note: Portland Fire & Rescue initially identified the neighbor that escaped the fire as a resident. This story has been updated to reflect that correction.

PORTLAND, Ore. (KOIN) — A body was found inside a duplex that went up in flames overnight Thursday in the Lloyd District, according to Portland Fire & Rescue.

Crews responded to the blaze at a two-story duplex on NE Halsey Street near 6th Avenue at about 11:16 p.m.

When firefighters arrived, two sides of the building were reportedly burning. As some firefighters worked to put the flames out, PF&R said others began searching for a neighbor that was reported to be inside.

While searching fire officials learned the neighbor made it out safely, but firefighters came across a body of a resident in one of the apartments. The person appeared to have died from natural causes prior to the fire, according to investigators.

The building was significantly damaged before crews brought the fire under control at 12:13 a.m. PF&R said the back stairwell was “completely burned through.”

PF&R said they are working to find the cause of the fire, and a medical examiner is investigating the cause of death.