Corrections officials said Timothy Richards, 42, was discovered missing from his bunk Sunday and couldn't be located during an inmate count, the Jasper Daily Mountain Eagle reported Monday.
The Alabama Department of Corrections and state and federal law enforcement agencies were assisting in the search.
Richards was sentenced to life in prison in February 2000 in Walker County after pleading guilty to his role in a murder plot with his wife, Shonda Johnson. Richards was Johnson's fifth husband and admitted killing her third husband in 1997. Johnson is on Alabama's death row after being sentenced to death in January 2000.