Mass shooting thwarted in Washington state: Teen planned chlorine bomb attack, FBI says

According to the local law enforcement, authorities interrupted a planned mass shooting and improvised explosive device (IED) attack targeting the Three Rivers Mall in Kelso, Washington.

A ‘meticulously developed’ attack

Law enforcement thwarted the chilling plot on May 22, 2025, when authorities arrested a juvenile suspect from Columbia County, Oregon, who had been conspiring to unleash a chlorine bomb explosion followed by a mass shooting.

A minor, whose name is withheld, “meticulously” developed the attack, the FBI said. This included creating a map of the mall, plotting an escape route, and coordinating the use of an improvised explosive device, in this case, a chlorine bomb.

The suspect, the FBI says, intended to create chaos and panic among mall patrons. The juvenile planned to follow the explosion by shooting individuals exiting the mall’s movie theater before ultimately taking their own life inside the building.

The FBI identified the suspect within 24 hours

The FBI received a tip about the planned attack on May 19, 2025, and swiftly launched an investigation. Within 24 hours, authorities identified the accused attacker through online chats where they shared violent extremist ideologies and details of their plot.

Law enforcement agencies initiated court-authorized surveillance and obtained a federal search warrant. Deputies from the Columbia County Sheriff’s Office arrested the minor on May 22, preventing what could have been a devastating mass casualty event.

“This plot was as serious as it gets,” stated Doug Olson, FBI Portland Special Agent in Charge. “We, along with our partners, moved swiftly to interrupt this violent plan and to protect our community.”

The Columbia County District Attorney’s office has taken up prosecution, charging the suspect under state law. The FBI has emphasized the importance of community vigilance, encouraging the public to report suspicious activities and urging parents to maintain open conversations with their children about online behavior.

What are chlorine bombs?

Chlorine bombs, a type of improvised explosive device, combine chlorine gas with explosive materials to cause harm through both blast and toxic gas release. Law enforcement and security reports have highlighted such devices. They are particularly dangerous in enclosed spaces such as malls, schools, and public transit hubs.

The combination of physical explosion and toxic exposure can cause mass panic and overwhelming injury, making them a favored tool for terror plots.

The thwarted attack fits into a broader pattern of increasing concern over domestic extremist plots in the United States. The FBI and Department of Homeland Security have repeatedly warned about young individuals becoming radicalized online, particularly through extremist ideologies promoting nihilism and violence.