Police in Clinton hope an old letter can give them some new leads in an unsolved case.

Angela Hammond was kidnapped 30-years ago, on April 4, 1991.

Hammond, who was pregnant at the time, was talking to her boyfriend on a payphone when she was taken.

Police think she was mistaken for another person who was named Angela.

A confidential informant, who also had a daughter named Angela, got a threatening letter after testifying in a drug case.

Then, a few months ago, someone left a voicemail for police talking about the contents of the letter.

Now, authorities want to talk with that person.