The Collector
(1965)

Freddy Clegg (Terence Stamp) is a wealthy butterfly collector who chloroforms and kidnaps art student Miranda Grey (Samantha Eggar).  He explains that he's been in secretly in love with her from the first moment he saw her.  After a failed escape attempt, Miranda agrees to stay a month to give her a chance to get to know him.  When the time comes, however, Freddy refuses to release her, and she hits him in the head with a shovel duing a rain storm.  He locks her in the cellar, accidently breaking her electric heater in the struggle, leaving her soaking wet and cold while he goes to the hospital.  He returns to find her deathly ill.  Freddy goes to town to get medical supplies, but Miranda has died.

When she last see Freddy he's in the van, stalking a Nurse from the hospital just as he did Miranda.

Thanks Chloe!