Body Double (1984)

Storyline:
After losing an acting role and his girlfriend, Jake Scully finally catches a break: he gets offered a gig house-sitting in the Hollywood Hills. While peering through the beautiful home's telescope one night, he spies a gorgeous woman dancing in her window. But when he witnesses the girl's murder, it leads Scully through the netherworld of the adult entertainment industry on a search for answers—with porn actress Holly Body as his guide.