A little seen English film, of excellent quality. Hayley Mills plays a young woman, whose life is infiltrated by a psychopathic young man, who pretends to be mentally handicapped in order to gain her trust. Not bloody, but a tense psychological thriller.
! No longer available (http://www.youtube.com/watch?v=KmqGOXMUmjY#)
Sadly, they no longer have the full movie at YouTube; still worth a look.
(https://i.jeded.com/i/twisted-nerve.2488.jpg)