A classic episode of "Alfred Hitchcock Presents" aired on television in 1958. "Lamb to the Slaughter" relates the grim tale of a wily housewife who, having murdered her husband with a frozen leg of lamb, cooks and serves it to the police investigating his murder -- who thereby conveniently eat the evidence.
Incredibly, Hitchcock had based the plot on a true story.
[In another memorable case, a woman stabbed her husband to death before eating the murder weapon: a shard of crusty cheese.]