(CNN) -- Investigators asked for help Thursday as they searched for a man seen in a mall in Littleton, Colorado, shortly before what they described as a possible attempt to bomb the shopping center on the 12th anniversary of the shooting at nearby Columbine High School.
Authorities told reporters at a news conference that the man they are seeking is a "person of interest," and they asked for help from the news media and public in identifying him.
No evidence exists so far of a link to the Columbine shootings, Jefferson County Sheriff Ted Mink said, but he acknowledged the possibility was on the minds of law enforcement officials.
"There's not a definite link that we have right now to anything at Columbine other than the date," Mink said, adding that the April 20th anniversary of the shootings "is fresh on everyone's mind."
A security camera shows the man sought by authorities in the mall just minutes before a security guard noticed a fire. Investigators say that fire may have been part of an attempt to detonate explosives.
The incident happened Wednesday at the Southwest Plaza Mall, less than two miles from Columbine High School. It came on the 12th anniversary of the shooting at Columbine that left 12 students and a teacher dead at the hands of two other students, who then killed themselves.
"It's sort of scary, but it's also ... terrible," said David Cullen, author of the book "Columbine" about the massacre. "It's like attacking people who are in mourning."
Law-enforcement officials released surveillance camera images of a man carrying a white plastic bag at the mall around noon. He was in a part of the mall that the public does not usually access.
Only minutes after he was seen in the area, a security guard noticed a small fire there and quickly put it out. A subsequent search turned up explosives, said Jacki Kelley of the Jefferson County Sheriff's office.
"The propane tanks and the pipe bomb were literally together," she told reporters Wednesday night at a news conference.
The mall was quickly evacuated and no one was hurt, authorities said.
Mink said that the mall had been thoroughly searched and was allowed to reopen on Thursday. None of the authorities who spoke at the news conference provided further information on the explosives found at the scene, saying they needed to interview more people and didn't want details reported in the media to influence any responses they might get.
The situation could have been much worse, said Dave Joly, a spokesman for the FBI.
"Depending (on) if it went off and actively combusted as what it was set to do, it could have been more serious than it was," he said at an earlier news conference, adding that it appeared that the pipe bomb was supposed to be a trigger to detonate the propane tanks.
"This was potentially devastating to a very high populated area, and very difficult to ignore the day that today is," Kelley added.
"We're not ignoring that. The date is significant to Colorado history," Joly added.
Schools in the area were briefly put on lockdown, according to the sheriff's office. Columbine High School was already closed Wednesday, for what its school calendar called a staff development day.
The person authorities want to talk to is described as a white male with gray hair and a silver mustache, the FBI said. He wore a dark cap with a light-colored logo on the front, a gray and white horizontally striped shirt, a dark jacket, jeans and dark-colored shoes.
"We're not sure if he's a suspect or a possible witness," Kelley said.
CNN's Jeanne Meserve contributed to this report.