Richland police have arrested a 22-year-old Pasco man for firing a gun during the July 4 celebration in Howard Amon park, but say he's NOT the one who shot 24-year-old Sergio Rivera.

Rivera was part of one of two groups of people who confronted each other in the park, and was shot.

The man in custody is Zachary, Box, who was illegally possessing a firearm. They did not say however, if he was directly related to the altercation. Rivera remains in serious condition in Kadlec Regional Medical Center, as he was shot several times. Police say he and the shooter knew each other.