ARAPAHOE COUNTY — South Metro Fire crews found an adult dead inside a burning duplex south of Cherry Creek State Park early Sunday morning, the department tweeted.

When firefighters arrived on scene around 4 a.m. Sunday, they could see flames coming from the basement, first floor and second floor of the duplex in the 5500 block of South Lansing Way in unincorporated Arapahoe County, a spokesman for South Metro Fire Rescue said.

Neighboring homes were evacuated until the department could get the fire under control.

The gender of the person who died has not been released. No other occupants were inside and no one else was injured, South Metro Fire tweeted.

Investigators on scene are working to determine the cause of the fire.