Sounds like 'Fright Night' from 1985. It's a horror movie, shot in color, about a suburban teenager who discovers a vampire has moved in next door. In the first 20 minutes, the teen watches through his window as the vampire kills victims in his house, moves a coffin into the basement, and the vampire's minion disposes of corpses in the middle of the night, all set to ominous music. Of course, no one believes the teen. It's an American movie but features British actor Roddy McDowall. It's an underrated classic, streaming now on HBO Max.