An 18-year-old has been arrested in Washington state on suspicion of manslaughter and arson in connection with a deadly July 4 fire.

The Douglas County Sheriff's Office stated that the incident began when a group of individuals were setting off illegal fireworks from the back of a truck. One firework reportedly landed in roadside brush, igniting a fast-moving blaze.

Authorities are also seeking arrest warrants for five other individuals believed to be over 18 and complicit in the same crimes. Sheriff Tyler Caille urged the remaining suspects to surrender to law enforcement.

The Chelan Hills Fire, as it was designated, burned approximately 15.6 square miles and consumed more than 100 structures. Robert Lister, a 69-year-old resident of Orondo, was identified as the sole fatality. His vehicle had reportedly slid off the road and was engulfed by the flames.