Luton murders: video allegedly posted by killer raises questions over motive

Clip allegedly posted online by Nicholas Prosper says he was chosen' by video game character

Nineteen-year-old Nicholas Prosper spent much of his time online. This is hardly uncommon for modern teenagers, but Prosper - who rarely left home - was so immersed in the digital world that some of his neighbours reportedly had no idea he existed.

That changed last September when people in Leabank Tower, Luton, were startled by the sounds of screams and gunshots in the early hours. Prosper, who was 18 at the time, had shot his mother, Juliana Falcon, 48, and siblings Kyle Falcon, 16, and Giselle Falcon, 13, in the head. Police said that when they arrived at the scene they were met with such awful circumstances".