(CNN) -- A 65-year-old ex-convict suspected of leaving a homemade bomb in a suburban Denver mall pleaded not guilty Friday to federal charges of arson and use of a destructive device, the Justice Department said.
U.S. Magistrate Judge Boyd N. Boland ordered Earl Albert Moore held without bond pending a resolution of the case.
A federal grand jury in Denver indicted Moore late Thursday.
Boulder, Colorado, police arrested Moore on April 26 after receiving a tip from a grocery store employee who recognized him from photographs released by the FBI.
Moore had first been charged on April 24 in a sealed criminal complaint. He made his initial appearance in U.S. District Court in Denver on April 27. Friday's indictment formalizes the charges against Moore, who remains in federal custody.
According to an affidavit filed in support of the arrest warrant, Moore entered Southwest Plaza Mall on April 20 via an employee-only entrance, then put a homemade bomb inside an employee corridor and left. As he was leaving, a fire erupted, but the device did not explode. A security officer put out the fire with a fire extinguisher.
According to court documents, Moore was linked to the explosive device by DNA recovered from the bomb.
If convicted of arson of a building, he faces five to 20 years in federal prison, and a fine of up to $250,000. If convicted of use of a destructive device during and in relation to a crime of violence, he faces at least 30 years consecutive to any other sentence imposed, and a fine of up to $250,000.
U.S. District Court Judge John L. Kane has set a tentative trial date of July 11. Officials have suggested no motive.
The incident occurred on the 12th anniversary of the Columbine school massacre in which 12 students and a teacher were killed. The mall's location near Columbine high school led to speculation that the two incidents were connected.
But Jefferson County Colorado Sheriff Ted Mink has ruled out any connection between the events.
"This incident had no bearing on any of the schools in the Littleton school district," Mink told reporters last month. "There was absolutely no connection."
Just seven days before the incident, Moore was released from federal prison in South Carolina, where he had been serving a sentence for a 2005 bank robbery in West Virginia.