An Oregon teen has been arrested in connection with an alleged mass shooting plot targeting the Three Rivers Mall in Kelso, in southwestern Washington, officials said. The suspect, whose identity has not been disclosed due to his age,

The plot, described by one official as being “as serious as it gets,” involved a plan to shoot moviegoers at a Washington State mall as they fled an explosion.

A teen suspect has been arrested in connection with a planned mass shooting at Three Rivers Mall in Kelso, Wash., FBI Portland announced.