HAZELWOOD, Mo. (AP) — One man is dead and another is hospitalized in critical condition after a shooting on a suburban St. Louis interstate highway.

The shooting happened about 1:30 a.m. Sunday on Interstate 170 in north St. Louis County. Officers discovered a black Infinity SUV on the shoulder of the road with several bullet holes.

The driver, 32-year-old Brian Valley, was pronounced dead at the scene. A 31-year-old passenger is hospitalized with gunshot wounds to the arm and back.

Police say the men had been at a high school reunion party when an altercation occurred. No arrests have been made.

The Greater St. Louis Area Major Case Squad is investigating.