Jason Eugene Bush, also known as "Gunny," was born on August 11, 1974, in LaGrande, Oregon. He grew up in a challenging environment, although specific details about his childhood are not widely known. As he got older, Bush faced legal troubles that shaped his early adult life.

In 1997, he had a significant run-in with the law when he was charged with the execution-style killing of Jonathan Bumstead, who was associated with the Aryan Nations. This act was supposedly motivated by Bumstead being labeled a "race-traitor." That same year, Bush was also imprisoned for other crimes, including car theft and possession of a firearm, which was illegal due to his prior felony conviction.

After serving time, Bush was released from prison in 2003. He then moved to Sandpoint, Idaho, where he lived until 2007. During this time, he was believed to have connections with white supremacist groups, such as the Aryan Nations.

Bush's life continued to be marked by violence and criminal behavior. He was suspected of being involved in two additional killings in 1997. Witnesses alleged that he had appeared at friends' homes covered in blood, suggesting he had committed violent acts.

As he grew older, Bush became involved with the Minutemen American Defense (MAD), where he held the position of National Director of Operations.

On May 30, 2009, Jason Eugene Bush was involved in a violent home invasion in Arivaca, Arizona. Along with his accomplices, Shawna Forde and Albert Gaxiola, Bush entered the home of Raul Flores Jr. and his daughter, Brisenia. The group falsely claimed they were law enforcement officers looking for fugitives. Their intention was to search for money and drugs to finance their nativist group, the Minutemen American Defense (MAD).

When they did not find any drugs, the attackers stole some inexpensive jewelry. During the invasion, they shot and killed Raul Flores Jr., who was 29 years old, and his nine-year-old daughter, Brisenia. Gina Gonzales, Raul's wife and Brisenia's mother, was also inside the home. She was shot three times but survived by pretending to be dead. After the attackers left, she managed to call 9-1-1 for help.

While on the call, the attackers returned to the house. In a desperate act of self-defense, Gina exchanged gunfire with them, injuring Bush in the leg. After the attack, Bush received medical treatment for his injury.

Gina Gonzales identified Bush as one of the attackers. The day after the murders, police found Bush's leg injury significant as evidence linking him to the crime. Following the home invasion, Bush was arrested and faced trial for the murders. In 2011, he was convicted and sentenced to death for his role in the crimes.

In addition to the murders of Raul and Brisenia Flores, Bush had been connected to other violent incidents. He faced charges for a 1997 murder based on DNA evidence. His criminal history included previous convictions for serious offenses. After exhausting his appeal process, Bush's death sentence was upheld in 2018.