Fire investigators are looking into what caused a blaze in a building on Bijou west of I-25 on Tuesday.
A neighbor contacted the fire department about smoke at the old Denny’s restaurant at about 3:40.
When firefighters arrived, they declared a second alarm.
40 firemen battled the flames which looked to have started on the outside of the building.
Crews were on the scene for hours checking on hotspots.
Denny’s has been closed for 2 years and the building is vacant.
No one was injured.