Frenzy (1972) ending / spoiler
Bob Rusk is the neck tie killer. He frames Blaney by putting a recent victim's clothes (the girl he placed in the potato sack) in Blaney's bag and then tells the police. Blaney's jail mates put sleeping pills in a guard's drink; during the commotion he escapes and heads to Rusk's place with revenge in mind. Inspector Oxford with help from his wife, goes over the case during dinner and arrives to the conclusion that Blaney isn't the killer and that Bob Rusk was spotted near a diner the night the girl in the potato sack was found so Blaney was telling the truth and Rusk is the killer. Oxford hears of Blaney's escape and heads to Rusk's place. When Blaney arrives to Rusk's apartment, he discovers a dead woman in bed (a recent victim) and moments later, Oxford shows up and of course, because of the woman, thinks that Blaney is the killer. As Blaney is saying "this is not what it looks like! I didn't do this!", he and Oxford hear someone approaching. It is Rusk... carrying a large suitcase... busted!
Submitted by Frinkmeister