Neville Harris was a recurring character in Season 1 of Guilt. He is portrayed by Ryan Gerald. He was Molly Ryan's stalker, and watched her through his window, and apparently even witnessed her murder by Prince Theo.
He was killed in the episode The Crown v Atwood, though the situation was painted as a suicide.
Neville is a sweet guy who lives with his mother, and had a major crush on Molly, and would watch her through his window. After luring Grace to his workshop, and holding a knife to her throat in an effort by her to escape, he was sent to a mental institution for treatment.