Intruder (1989)

So the killer in this movie is supposed to be a surprise at the end, but I guess whoever made the trailer didn't realize that because it really goes out of its way to show you who the killer is about a million times. HOWEVER, if you already watched the trailer, don't worry. The end has another fun twist that's pretty worthwhile.

Oh, and if you think you recognize a familiar face, it's Renee Estevez! She's Molly in Sleepaway Camp II and Winona Ryder's nerdy friend Betty in Heathers, and sister to Charlie Sheen and Emilio Estevez. I wonder if she ever does horror cons? I would like to get her autograph.