One person died in a fire downtown Tuesday morning near 36th St. and Wazee Street, the Denver Fire Department said.It's being investigated as arson, according to DFD. Six Denver police officers and another three Denver fire investigators were working together on the investigation Tuesday morning, according to Cedillo. No other injuries were reported. Denver firefighters responded around 7:05 a.m. Tuesday to what the department called a "commercial structure fire." But Luis Cedillo, the public information officer with the Denver Fire Department, later clarified it's an abandoned building. Crews had to enter through a window because the doors of the building were welded shut. Cedillo estimated the area would be blocked off for the rest of the morning as crews investigate.