In the search for a suspect in an attempted bombing Wednesday morning at a Colorado mall, a number of similarities are appearing from the 1999 Columbine High School shooting.
The incident involving mysterious explosives found at the Southwest Plaza Mall in Littleton came 12 years to the day after the shooting rampage at Columbine High School, which is located just one mile from the mall.
And just like Columbine, an unexploded pipe bomb and propane tanks were discovered inside the mall.
"We're concerned about the date, the time, things of that nature, but we don't have anything solid that would indicate any link at all other than, certainly, circumstances," Jefferson County Sheriff Ted Mink said Thursday.
The Columbine shootings started at 11:19 a.m. and ended at 12:08 p.m. on April 20, 1999, with the suicides of the two teenage gunmen. Unexploded pipe bombs and propane tanks with explosives attached were found in the school cafeteria after the shooting.
"The kind of crime like Columbine will motivate a certain segment of the population to attempt the same type of crime," said Brian Rohrbough, whose son Daniel was killed at Columbine. "Whether they're doing it because they're purely evil or in addition to being evil, they just want attention, I don't know."
Authorities have a number of leads -- but no arrests yet -- in their search for a suspect .
The FBI has released two images of a "person of interest" that were recorded on surveillance video, and investigators are asking for the public's help in identifying the man.
"He's a person of interest, not a suspect," Jefferson County Sheriff's Department spokeswoman Jackie Kelley said. "He was in the area, so he may be a witness."
Law enforcement said during a news conference Thursday that no motive has been identified. They also say it's unclear whether the attempt was meant to coincide with the 12th year anniversary of the Columbine massacre, in which a teacher and 12 students were murdered by two fellow students, who eventually took their own lives.
"Whether it’s coincidental or not, that's something we’re looking at very seriously," Jefferson County Sheriff Ted Mink told reporters.
Police describe the "person of interest" as a white male with graying hair and a silver mustache. He was wearing a dark cap with a light logo on the front, along with a shirt with gray and white horizontal stripes, dark jacket with silver buttons, blue jeans, and dark shoes.
The first device was found at about 11:50 a.m., when a mall employee noticed a fire in a hallway near the food court, the witness told Fox 31. The worker immediately contacted security officers, who began evacuating the sprawling indoor shopping center.
The employee said the device was attached to two camping propane tanks, neither of which exploded.
The Jefferson County Bomb Squad responded and later found a pipe bomb in the same hallway, Kelley said.
When crews tried to explode the pipe bomb using a remote-controlled robot, it appeared to fall apart and detonation became unnecessary.
Kelley refused to elaborate on the level of sophistication involved in the bombs' designs, but she did say the bombs could have been potentially devastating to such a high traffic area.
“We obviously have a suspect who is still at large. We have a case that we want to prosecute and an arrest we want to make, so we’re going to be a little tight-lipped around that,” Kelley said earlier Wednesday afternoon.
The mall remained closed for the remainder of the night.
The Federal Bureau of Investigation confirms that it is assisting in the investigation, but would not immediately classify this as a case of domestic terrorism.
"It's too early to speculate," FBI spokesman Dave Joly told Fox 31. He said the devices could have caused "serious" damage, if they had detonated.
More than two dozen Jefferson County schools were placed on lockout as a precaution, meaning there was only one point of entry and exit for each school.
Investigators are asking anyone who recognizes the man or who witnessed suspicious activities at the mall to contact the Jefferson County Tip Line at 303-271-5615.