A preliminary hearing is July 29 for an Arizona man charged with first-degree murder in Pike County, Illinois.

28-year-old Joseph Coffman is accused in the stabbing death of his half-brother, 47-year-old Dennis Coffman.

The incident allegedly took place early Saturday morning as the two men were driving along a stretch of Interstate 72 near the Hull exit just east of the Mark Twain Bridge at Hannibal.

Authorities have said the two men may have gotten into a fight, but have not offered a motive.