DENVER (CBS4) – A federal court in Denver on Thursday afternoon sentenced a man who admits he attempted to bomb Southwest Plaza Mall nearly a year ago.

Earl Albert Moore already pleaded guilty in December to a federal charge of using a destructive device in relation to a violent crime. He will now go to prison for life.

The propane tanks and a pipe bomb were planted in the Jefferson County shopping mall in April 2011. Moore started a small fire that led to an evacuation of the mall and the detonation of the bomb, which turned out to be a very minor explosion. No one was hurt and there was minimal damage.

Moore said in court in December he drained the propane from the tanks and didn’t intend to harm anyone. He said that he did it because he was upset about a domestic situation. Moore’s ex-wife apparently worked at the mall at one time.

He was arrested in Boulder five days after the April 20 incident after being identified in surveillance video images and after investigators found his DNA on the explosive device.

Moore has an extensive criminal background. He was released from prison in South Carolina a week before the bombing attempt.

The crime happened on the same day as the 12th anniversary of the shootings at the nearby Columbine High School. In a letter Moore mailed to CBS4 investigator Rick Sallinger after he was arrested he wrote that there was no connection to Columbine.