Screenwriting : Ownership/Distribution rights by Dave Gutosky

Greetings Stage 32 family. I am an aspiring screenwriter from the Midwest, Iowa to be more specific. As you can imagine, the internet is my best connection to the movie business. How does one go about finding out who owns the rights to a particular story/characters? I have done some digging on my own but continue to come up empty. I am hoping someone from the Stage 32 community can help point me in the right direction. I am in search of the person or persons who own the rights to the story and/or characters from the 1975 ABC TV movie Trilogy of Terror, specifically the short story by Richard Matheson, Prey. As most of you know Prey was adapted into the short Amelia, the third and most memorable story of the trilogy. It was produced by Dan Curtis Productions and ABC Circle Films. The movie has been distributed multiple times by different companies from around the world. I have contacted a few of them with little or no response. It most recently has become available for Amazon Prime members. I am also interested in the same for the 1996 Trilogy of Terror II which aired on the USA Network and was produced by Dan Curtis Productions along with Power Pictures in association with Wilshire Court productions. My screenplay meshes the two stories into one full length screenplay. Any help would be greatly appreciated. Thank you!