WARNING: DISTRESSING CONTENT. Dylan Phelan has been sentenced to six years and four months for encouraging vulnerable Travis Dyer to die by suicide on a twisted video call. But what drives this warped online behaviour?

WARNING: DISTRESSING DETAILS - Dylan Phelan, from Leeds, encouraged a 'vulnerable' 21-year-old man in America to take his own life during a two-minute video call

Dylan Phelan kept a recording of the suicide on his computer