"I love my wife!"
Allen was depressed to the point of suicidal feelings and had low self-esteem. As a result, he was forced to attend numerous support groups. He became jealous of his good friend Grant Ford when he married a woman named Brenda and had a child with her, a girl they named Hannah. Grant, a U.S. Navy SEAL, was later deployed to Afghanistan, where he was later killed in action. Allen saw an opportunity to live out the happiness he wanted and took advantage of Brenda's grief, eventually getting her to have feelings for him. The two married and Allen raised Hannah together with Brenda, although he continued to feel as if he was living under Grant's shadow. He gradually developed a desire to become a hero in Brenda's eyes, like Grant was. One day, he learned of a bombing at Delancy Elementary School that killed a school custodian working the graveyard shift. This inspired him to emulate the incident so he could save innocent lives and be branded a hero in the community. Allen recovered explosive-making manuals that belonged to Grant, who was an explosive ordnance specialist, and used them as guidelines to construct a bomb modeled after the one that destroyed the elementary school.
Allen placed the bomb he constructed in the bathroom of a crowded coffee shop called Indy's Best Brew. He planned to save the life of a pregnant woman who was using the bathroom at the time, and was the most sympathetic victim he could find. The toilet bowl Allen put the bomb in contained most of the initial explosion. However, to Allen's shock, the first explosion ruptured a natural gas line, which triggered a second, more violent explosion, killing seven people, wounding fourteen others (including the pregnant woman), and giving Allen a broken arm. The BAU began investigating and believed the bombing was connected to the one at Delancy Elementary. Kate and JJ first visit Allen at his home to talk to him as a witness. While interviewing him, Allen tries to convince them the bombing was a terrorist attack while Brenda tells them about her first husband, Grant, and how Allen introduced them. Allen then learns that the pregnant woman survived and delivered her baby safely, to his relief. After the interview, a mob of reporters gather outside Allen's house to interview him. As Allen and Brenda don't want to be interviewed anymore, Kate and JJ distract the reporters long enough for them to sneak out through the backdoor and get to Allen's truck in the driveway.
Later that night, Brenda tells Hannah about how brave and heroic he was for saving the woman and her baby at Indy's Best Brew, giving Allen the admiration he desired. Allen then leaves, claiming to go to the store, but when he gets in his truck, he begins crying after reading a news article about the people he killed. When he tries to drive away, he feels something click and looks down to see wires connected to the truck's gas pedal, realizing there is a bomb inside the truck. Allen tells Brenda and Hannah to leave so they aren't killed, just as Reid, Morgan, and several police officers arrive on the scene. Realizing the bomb squad won't get there in time, Morgan attempts to defuse the bomb himself using a knife from Allen's glove box. Despite difficulties in choosing which wire to cut, Morgan successfully defuses the bomb. Later, after Garcia looks into his history, the BAU later discovers that Allen was the person who bombed Indy's Best Brew, while the person behind the Delancy Elementary bombing planted the bomb under Allen's truck, with the intention of killing him out of jealousy for diverting the media's attention away from him. During interrogation, Allen confesses to his crimes to the BAU and was arrested, but not before the team had him stage a fake award ceremony to lure the other bomber out.
During the coffee shop bombing, Allen used a bomb made of TNT, exactly like the one used in the elementary school bombing. He set it inside a unisex bathroom and allowed a pregnant woman to use it first. Then, once the bomb detonated harmlessly and injured the woman, he would spring into action and save her. However, he unknowingly set the bomb near the gas main, which triggered a second, more devastating explosion.
No official profile of Allen was made by the BAU, who were more focused on Burke.
Allen's situation is similar to Juan Manuel Álvarez, who directly caused a deadly train crash at Glendale, California, on January 26, 2005. Both carried out the respective incidents unintentionally while trying to stage something on a smaller scale (Allen was intending to inflict injury on only one person that he would then save, while Álvarez attempted to commit suicide by having the train ram through his SUV) and then tried to evade suspicion afterwards. Also, Allen's low self-esteem and suicidal feelings might be a reference to Álvarez's own suicidal tendencies.
Allen may also have been inspired in part by Richard Jewell, a man who helped to minimize the damage caused by the Centennial Olympic Park bombing committed by Eric Rudolph. Both acted to save lives during the respective bombings and were initially lauded as heroes by the media as a result. However, they were then treated as suspects in the resulting FBI investigations, and theories arose that both planted the bombs to engineer situations in which they emerged as heroes. The major difference between Allen and Jewell is that Jewell was later deemed to be innocent, while Allen did orchestrate his own bombing (even though the magnitude of the destruction was larger than what he had planned) for that exact reason.
All of the following were attacked in the February 3, 2015 Indy's Best Brew coffee shop bombing
- Pat Aguilar (survived the explosion, but died of his wounds at a hospital)
- Grace Calvern
- Joe Gardez
- Scott Legford
- Jackson Novert
- Ryan Spatman
- Bree Wanfield
- Jordan Aguilar (Pat Aguilar's son)
- An unnamed woman (was pregnant at the time of the bombing; her baby was delivered safely)
- Twelve other unnamed people