Crum was in his police vehicle outside the courthouse in downtown Williamson just after noon EDT when a man got out of another vehicle, walked to Crum's vehicle and shot him, witnesses told the Williamson Daily News.
WKYT-TV, Lexington, Ky., said officials in the office of Williamson Mayor Darrin McCormick confirmed Crum was killed in the shooting. No possible motive was reported.
The TV station said the courthouse was put on lockdown.
The suspect, identified as Tennis Melvin Maynard, 37, was undergoing surgery Wednesday at Cabell Huntington Hospital in Huntington, WCHS-TV, Charleston-Huntington, W.Va., reported.
Virginia State Police said a sheriff's deputy spotted Maynard's vehicle and rammed it with his police vehicle, causing Maynard to crash. Maynard was shot when he got out of his vehicle holding a gun, police said.
A candlelight vigil for Crum was scheduled for Thursday evening at the Mingo County Courthouse.
WOWK-TV, Charleston-Huntington, said Crum was known as tough on crime.