Death penalty opponents are using the 25th anniversary of Missouri's resumption of capital punishment to highlight their desire to halt executions.
George Mercer was executed on Jan. 6, 1989, for the 1978 rape and slaying of waitress Karen Keeten in the Kansas City area. Mercer's execution was Missouri's first after a nationwide moratorium on capital punishment was lifted in 1976.
Since then, Missouri has executed 70 inmates.
Death penalty opponents planned a news conference Monday at the Missouri Capitol.
Missouri slowed its execution pace in recent years during court challenges to its procedures.
But it executed two people in the past two months and is scheduled to execute Herbert Smulls on Jan. 29 for the 1991 robbery and slaying of suburban St. Louis jewelry store owner Stephen Honickman.