The FBI said Earl Albert Moore is considered armed and dangerous and has an extensive criminal background.
The bombing attempt was discovered Wednesday when firefighters outside Denver found a pipe bomb and propane tanks near a Littleton mall's food court. The devices did not explode.
Moore is described as a Caucasian male, 6 feet 2 inches tall, between 200 and 225 pounds, bald, blue eyes, with a grey mustache. He was last seen wearing glasses, and has multiple tattoos.
On April 20, 1999 12 students and a teacher were killed by two students in the massacre at nearby Columbine High School.
The public is urged to call 911 if they know the whereabouts of Moore or the Jefferson County tip line at 303-271-5615 to provide any information.