A 23-year-old Birmingham man has been charged with attempted murder after police say he got into an argument with a stranger on the side of Interstate 20 and then chased him down and shot him.

Justin Chapman is charged with two counts of attempted murder and two counts of burglary, said Oxford police Chief Bill Partridge. He is facing additional charges.

Police say Chapman fired 21 shots during Thursday’s ordeal. The victim who was struck remains in critical condition.

Partridge said Chapman exited Interstate 20, drove recklessly along Alabama 21 and then got back up on the interstate.

At that point, Chapman stopped, jumped out of his vehicle and approached another man who was standing on the side of the interstate.

The two men did not know each other, Partridge said. An altercation ensued.

Another motorist in a Chevrolet Tahoe then pulled up and told the suspect to stop what he was doing.

Chapman brandished a semi-automatic rifle and shot one round in the Tahoe.

The man with whom the suspect had initially argued took off running toward the RaceTrac store on Alabama 21 and Grace Street.

Chapman pursued him and fired on him again at the entrance to RaceTrac. The wounded victim dropped to the ground.

The shooter then approached the store and fired multiple rounds into the business. The employees had heard the previous shots and locked the doors before he got to the store, the chief said.

Multiple police officers arrived at the scene. Partridge said Chapman then surrendered.

The victim was airlifted to UAB Hospital where he remains in critical condition.

Partridge said Friday investigators have not yet identified a motive in Chapman’s behavior.

Chapman is being held in the Oxford City Jail.