On Sept. 5, 2012, Aurora Barrera, seen here, walked into a Los Angeles bank where she was an assistant manager. She claimed to have been kidnapped, strapped with a bomb and forced into robbing her own bank. But police later determined Barrera was involved in the plot, helping to steal over $500,000. Pictured here is the device that the bomb squad learned was a fake bomb.

Leaving that morning to go to work, Barrera told police she went out to her garage, seen here, where two men held her at gunpoint and forced her to tape a device on her stomach. "It may be difficult to tell from this photograph, but the garage is tiny. It barely fits a small car in it," Special Agent Nicole Black told "20/20" about Barrera's story. “It would be very difficult, probably not feasible, for someone to hold a device, pull the shirt up, tear or cut tape, all while in a cramped garage while being held at gunpoint.”

Following what she told police were the kidnappers’ directions, Barrera then went to the bank. She enlisted the help of the only other employee in the bank to help her empty the vault. The only cash left in the vault, pictured here, were dollar bills (bottom) and damaged bills (top) set for destruction.

Barrera, pictured here (left) at the bank’s side door on bank surveillance video footage obtained by ABC News' "20/20," then threw the two bags with over half a million dollars out the bank's side door.

An accomplice, Richard Menchacca, pulled up on the side street in a car to pick up the money bags. A bank employee, seen here by a window on bank surveillance video, was able to see part of the license plate number. Menchacca passed the money to Bryan Perez, another accomplice who was waiting in a second car. "He tells me to go. He slapped the car, like, 'Get out of here,'" Perez told "20/20."

The bank employee saw part of the license plate number for this car, which was used to transport the money Barrera took from the bank’s vault.

A bomb squad then removed the device from Barrera’s stomach and destroyed it with the help of the squad’s robot. “I got down and pulled all the pieces apart and saw that there was no high explosives,” Sergeant Rob Harris told “20/20.” “It was not a bomb.”

Barrera's demeanor seen here on bank surveillance video was suspicious to police. "At times, she buttons her jacket or kind of tries to potentially hold the device up as if it may be falling off," Special Agent Nicole Black told "20/20." "A reasonable person that would think they had a device strapped on them that was going to blow up would be very cautious about how they manipulated it," Det. Joe Settles said.

In an interview with police after the incident, Barrera said she tore the electrical tape, seen here, use to attach the device with her own hands, without the help of the kidnappers. But the tape had clean edges, which meant it was cut with scissors, since electrical tape stretches when pulled. Police determined that her story did not add up. “It would have been very hard for her to hold what was a flashlight wrapped in duct tape with wires to her belly, tape it down and then reach around the side of her, cutting her own tape, and taping it onto the side of her body,” said Black.

The partial license plate number that Barrera’s co-worker saw led police to a car belonging to the father of Barrera’s then-boyfriend Ray Vega. Barrera and Vega were found guilty of conspiracy to commit bank robbery and bank robbery, with a special allegation of assault by use of a dangerous weapon. Barrera was sentenced to 9 years in prison. Vega was sentenced to 14 years in prison.

Accomplices, Menchacca and Perez, pleaded guilty and each received 5 years of probation and were ordered to pay restitution. They spent most of the stolen $150,000 they received, but the rest of the stolen money, which was about $400,000, was never found.