A federal grand jury has indicted Mark Adams Prieto, 58, of Prescott, Arizona, on charges of firearms trafficking, transferring a firearm for use in a hate crime and possession of an unregistered firearm. The U.S. Attorney’s Office for the District of Arizona announced the indictment this week, following an extensive investigation into Prieto’s alleged plan to commit a mass shooting targeting Black Americans and other minorities in an attempt to incite a race war before the 2024 presidential election.

According to the indictment, Prieto began discussions in January 2024 with two individuals he believed shared his racist beliefs. Unbeknownst to Prieto, these individuals were undercover FBI agents. The discussions involved detailed planning for a violent attack at a concert in Atlanta scheduled for May 14-15, 2024. The Hill reported that Prieto sold an AK-style rifle on February 25, 2024, and an AR-style rifle on March 24, 2024, to one of the undercover agents.

The FBI, in collaboration with the ATF, the Department of Veteran’s Affairs Office of Inspector General, the Arizona Attorney General’s Office and the Prescott Police Department, closely monitored Prieto’s activities. On May 14, 2024, law enforcement stopped Prieto while he was traveling east from Arizona through New Mexico on Interstate 40. At the time of his arrest, Prieto was in possession of seven firearms. Following his detention, authorities executed a search warrant at his residence in Prescott, where they discovered additional firearms, including an unregistered short-barreled rifle.

Each count of firearms trafficking and transferring a firearm for use in a hate crime carries a maximum penalty of 15 years in prison and a fine of $250,000. The charge for possessing an unregistered NFA firearm carries a maximum penalty of 10 years in prison and a fine of $250,000.

The U.S. Attorney’s Office for the District of Arizona, with support from the Department of Justice’s Civil Rights Division and National Security Division’s Counterterrorism Section, is overseeing the prosecution. The Phoenix FBI field office, along with the Albuquerque FBI field office and various state and local law enforcement agencies, conducted the investigation.