Link (1986) on Netflix

Student Jane jobs as an assistant for the animal researcher Phillip in a lonesome old house. They live alone except for the chimpanzees and butler Link: a 45 years old very intelligent orangutan. Phillip wants to put Link to death. However before he can do this he's vanished tracelessly one morning. Link starts behaving more and more aggressive and prohibits Jane from using the phone or reaching the next village. When she punishes him by locking him out, he becomes violent.