Authorities announced the charges Friday against 32-year-old Billie Jo Carson of East St. Louis and 26-year-old Dylon Baldwin of Caseyville. A judge ordered both held on $1 million bail.
Officials say Melvin Gregory of Conyers, Ga., suffered multiple stab wounds to his neck. Horseback riders found his body along a levee near Cahokia on Tuesday.
Authorities say a woman who cleaned up the crime scene and disposed of evidence also is charged with concealment of a homicidal death and obstructing justice in the case.
There's no word about a motive for the killing.