Authorities are trying to identify a person of interest on surveillance video in connection with of a pipe bomb and propane tanks found after a fire at a Littleton, Colo., mall on the 12th anniversary of the Columbine High School shooting.
"We ask for the community's support and help in identifying this individual," said Jefferson County Sheriff Ted Mink at a press conference today.
Authorities say the investigation is heading in the right direction and that they are following up on a lot of good leads.
The suspicious devices were found Wednesday afternoon at the Southwest Plaza Mall after firefighters responded to a small blaze in a hallway near the mall's food court. No one was injured and the devices did not explode.
An estimated 6,000 to 10,000 people were evacuated from the mall around noon. Officials said the fire caused some minor damage.
A source familiar with the case told ABC News that when officials responded they found some matches and a small fire in a service hallway that was put out by mall employees.
Authorities also discovered a bag from a Target store that contained paper, two Coleman propane tanks and a six-inch pipe that apparently was filled with smokeless powder, the source said. It appeared someone had tried to set the materials on fire, the source said, but it appeared the device would have produced a low-magnitude result, but one that could have injured people close by.
Authorities believe they have identified witnesses who saw the person of interest buy some of the materials, another source told ABC News.
The incident comes on the 12th anniversary of the Columbine High School shooting -- where two students opened fire and killed 12 students and one teacher on April 20, 1999.
The two teens, Eric Harris and Dylan Klebold, committed suicide after the massacre. They had left pipe bombs in the school but the majority of them did not explode.
It's unclear whether Wednesday's incident was connected to the shooting anniversary, but the mall is located near the high school.
"We're concerned about the date, the time and things of that nature, but we don't have anything solid that would indicate there's any link at all other than ... certainly circumstances," said Mink.
Late Wednesday night, FBI and law enforcement officials released a photo of a person of interest who was spotted on mall security cameras.
The person of interest was described as a white male with gray hair with a silver mustache.
He was wearing a dark cap, stripped shirt, blue jeans and dark shoes. In the surveillance photos, the man is seen holding a white plastic shopping bag.
"Surveillance tape gave a shot of an individual walking in with a bag, coming in a corridor that the public would not normally use. And this individual possibly witnessed someone maybe coming in or out that area at the same time or he could possibly be involved," said Joly.
Jacki Kelley with the Jefferson County Sheriff's Office said the man "is nothing more than a person of interest."
"We don't know whether he's somebody we need to look at as a suspect," Kelley said.
ABC News' Pierre Thomas contributed to this report.