DENVER—Denver firefighters are investigating the cause of a two-alarm blaze that gutted an office complex early Wednesday.
A passerby called 911 after spotting flames about 1:20 a.m. Firefighters found the complex fully involved in flames.
Denver Fire Department spokesman Lt. Phil Champagne says the roof of the building collapsed almost immediately, so crews attacked the fire from outside.
Some 65 firefighters brought the blaze under control in about two hours.
The building housed a bartenders school and was the former headquarters of the Republican Party in Denver.
Asst. Fire Chief Joe Hart says the building is a total loss.
Champagne says investigators may not be able to enter the building until Wednesday afternoon.
No injuries are reported.