This sounds like a movie adaptation. As such the copyright presumably belongs to the movie company. If the movie's copyright was renewed, I assume the comic would not be public domain either. But I'm no expert.
The comic would hold a separate copyright - the comic adaptation is a separate original work.
Yes, the have basis in the same script, but since the script is reworked and then the added element of artwork, it's a different and new work,it's not the same. Sorta like the situation with the LUX RADIO THEATER shows based on films.