DENVER (KDVR) — The Denver Fire Department is investigating a house fire that happened on Friday morning.

The fire started around 3 a.m. near 5th Avenue and Bannock Street. When firefighters arrived at the home, the encountered heavy fire.

Denver Fire Department

DFD said there was no one in the home at the time of the fire and they believe the home was vacant.

A firefighter was injured after stepping in a hole, DFD said.

Firefighters were able to get the fire under control in less than an hour.

Fire investigators are working to determine what caused the fire.