In June 2010, lone gunman Derrick Bird shot and killed 12 people and injured 11 more during a horrifying killing spree in the quiet Cumbria countryside.

Derrick Bird, the youngest of three brothers, is born with his twin brother David, on 27 November 1957, to Joseph and Mary Bird.

Growing up he meets a local woman, Linda Mills, at school. Eventually the couple settle and have two sons. They never marry and the relationship starts to crumble and ends in the early nineties. Bird moves into a pebble-dashed terraced house in the village of Rowrah and lives a quiet, respectable life as a taxi driver.

According to the people who live nearby Bird, 52, is the perfect neighbour: quiet, popular and fun to be with. When buying a pint of milk at his local shop, he always pays with a pound and leaves the change. He’s the sort of guy that when passing anyone on the street stops to say hello.

So what causes the perfect neighbour to become a killer overnight?