Seattle firefighters responding to a house fire on Capitol Hill late Wednesday afternoon recovered a man’s body from inside the residence, a fire department spokesperson confirmed.

The fire marshal, who was called to the scene along with members of the Seattle Police Department’s Arson & Bomb Squad, determined the fire was accidental, Seattle police spokesperson Valerie Carson wrote Wednesday in a text message. The fire department later said the blaze was likely caused by a portable space heater placed too close to combustible materials.

According to the Seattle Fire Department’s online 911 log, firefighters were dispatched to a building in the 1600 block of 18th Avenue just after 5:20 p.m. The department also posted about the discovery of a body on Twitter and announced Seattle police were called to aid in the investigation.

When firefighters arrived, the right front corner of the two-story house was in flames and heavy smoke was pouring from the residence, according to a post on the Seattle Fire Department’s blog. Neighbors told fire crews the home’s single occupant was unaccounted for and firefighters found him in what was described in the blog as “the fire room.” The fire was knocked down in 15 minutes and fully extinguished in 30 minutes, the blog post says.

Aside from the victim’s gender, no further details were provided.