Stjepan | Answers

Maybe Twilight's Last Gleaming from 1977? https://www.imdb.com/title/tt0076845/?ref_=ttls_li_tt

Maybe one of the versions of a German story "Geheimnis des blauen Zimmers" (usually translated as "Murder/Secret in the Blue Room") by Arnold Lippschütz: https://www.imdb.com/title/tt0022929/?ref_=nm_flmg_wr_7...

https://en.wikipedia.org/wiki/The_Blood_of_a_Poet ?

https://www.imdb.com/title/tt0046026/ The Magnetic Monster from 1953?