DENVER, Colo. -

The man police said planted a pipe bomb at a Littleton mall was released from prison one week before the incident. A nation-wide manhunt is underway for Earl Albert Moore, 65, who's accused of planting the explosives Wednesday, the anniversary of the Columbine High School shootings.

Moore is considered armed and dangerous. The FBI confirmed that he had been serving time in a Georgia prison for a 2005 armed robbery in West Virginia. Moore had been sentenced to 18 years, but was released early on April 13.

Authorities said just seven days later, he planted a pipe bomb at the Southwest Plaza Mall. Now, Moore is on the run.

"We followed all the local leads that we've been able to come up with, all the addresses and locations where he might be located," said Dave Joly, spokesperson for the Denver FBI office. "Those haven't been successful."

The search has gone national, with the Denver FBI sending photos of Moore to all 56 U.S. FBI offices.

KRDO Newschannel13 found out that Moore has a criminal history in Colorado spanning two decades. He's been arrested for drugs and larceny, and has a 2004 felony conviction for possession of burglary tools.

"We consider Moore armed and dangerous," said Joly. "He has an extensive criminal history, and we're asking for the public's help to view the photos to see if they've viewed him somewhere."

The FBI said Moore is about 6 feet or 6 feet 2 inches tall. They said he's between 200 and 250 lbs. with blue eyes, a bald head and a gray mustache. Moore has three tattoos on his arms; a Viking, a rose and a heart with a dagger through it.

If you have any information on Moore, call the Jefferson County Sheriff's Office at 303-271-5615 or call 911.