Chilling moment knife obsessed teen flees after stabbing 18-year-old through heart

A balaclava-clad teenager who had an 'unhealthy interest' in knives grinned before fatally stabbing an 18-year-old man through the heart with a Rambo-style knife, a murder trial has heard. The alleged attack happened on the evening of December 28 last year with the knife he kept hidden in his tracksuit bottoms.