They learn how to trek through the woods in the dark, use a hunting knife and make their own meals.

WSJ: Ah, Wilderness! Mountain Man vs. the Building Inspector

Forensic scientist Christopher Mckenzie said a 17cm-long (6.5in) hunting knife found at the scene had DNA on it from the three children.

BBC: Fuller quarry children 'stabbed to death'

It is alleged they found Mr Millar in Manton Street and he was attacked with a large hunting knife at about 01:30 BST.

BBC: Roger Millar