An apparent attempted bombing at a Colorado shopping mall was not likely related to the 12-year anniversary of the shootings at nearby Columbine High School, the FBI said.
Investigators have determined a motive but aren't releasing additional information, FBI Denver spokesman Dave Joly said Monday.
The agency on Sunday alerted field offices covering all 50 states and Puerto Rico to be on the lookout for Earl Albert Moore, 65.
Moore has been named the suspect in Wednesday's fire at Southwest Plaza Mall, about 2 miles from Columbine, where 12 students and a teacher were killed in 1999.
Authorities discovered a pipe bomb and two propane tanks after the fire, raising fears that the incident was timed to coincide with the anniversary.
Federal Bureau of Prisons records show that Moore was released from prison April 13.
Moore served time in a Georgia federal prison, Joly said. Federal court records show that Moore pleaded guilty in May 2005 to robbing a bank in Crab Orchard, W.Va., of $2,546.
A judge sentenced Moore to between 15 and 19 years in prison, but a federal appeals court in 2006 ruled his stiff sentence was "unreasonable" and Moore's sentence was reduced to seven years.
Colorado authorities said they discovered a pipe bomb and two propane tanks in a hallway of the mall's food court after firefighters responded to a fire. The explosives, which did not detonate, were found after the fire in the hallway prompted an evacuation of the mall. No one was injured.
Moore has an extensive criminal record and should be considered dangerous, federal officials said.
Colorado Bureau of Investigation records show several arrests for possession of dangerous drugs, theft, and possession of burglary tools dating to 1984. Court records show that an arrest warrant had been issued for Moore in September 2004, six months before the West Virginia bank robbery, for his failure to appear at a court hearing related to a burglary case.
Moore has used at least seven aliases that include variations of the names Earl Albert Buchannan, Donald Charles Morelli and Gary Steele, according to state arrest records.
Moore lived in Colorado at least part time from the mid-1980s to 2004, according to public records.
James Wicks, a former son-in-law living in Denver, said he was previously married to Moore's stepdaughter, Rebecca Duncan Wicks, who has since moved out of state. He declined to provide additional details when The Associated Press reached him at his home Sunday evening.
No one answered the door at Moore's last known address in south Denver, and neighbors said a young couple now lives there.
"If I would have recognized him on TV I would have called police," said Bill Newcomb, a tenant at the apartment complex where Moore once lived.
"It freaks me out," said Joy DeBoer, who recently moved into the complex with her husband, Jordan DeBoer. "Just knowing that he knows where this is and knowing that this is a place he would be familiar with — it's scary for me."
Investigators have exhausted all leads locally and have put out an alert to every FBI office the country, Joly said.
"Last time we knew where he was locally was around noon Wednesday at the mall," he said, referring to the previously released surveillance photos showing a man believed to be Moore in a hallway accessible only to employees and the suspect carrying a plastic shopping bag while riding an escalator. Other photos show a man believed to be Moore riding a public bus leaving the mall the night before the fire.
Moore is described as being between 6 feet and 6 feet, 2 inches tall and weighing about 200 to 225 pounds. He's bald with blue eyes and a grey mustache and has a tattoo of a Viking on each arm.