I saw this show on TV back in the spring of 1994, and I'm pretty sure it was In The Heat of the Night.

In this episode, detectives were talking to a couple outside their house. One of the detectives took a small doll out of a brown paper lunch bag. The doll was made from a black sock that had been stuffed and tied off to make a round head. It had wide eyes made from white felt circles with centered black pupils and a red circle for a mouth. It wore a blue baseball cap made of felt, and had the body of an octopus, or it may have been a person. Around the neck was a small white noose. The woman took it and went inside, crying. I remember asking my mom what that meant, and she said it meant death, so I think it was a voodoo threat to the couple's son.

So far I have tried Google and Wikipedia searches and searched TV.com and Epguides for In The Heat of The Night episodes. It isn't the voodoo episode "Don't Look Back", nor other shows like Beauty and The Beast's "Dark Spirit" and Murder She Wrote's "Big Easy Murder". I'm pretty sure it was In The Heat of The Night", since I also remember seeing "The Pig Woman of Sparta" around this time. The latest date for any of these would be 1994. So far I haven't been able to find a summary that matches this.