The murder of the innocent Liverpool schoolboy, Rhys Jones, shocked the country.
Watch preview of Panorama: Young Gunmen.
Rhys, 11, was shot in the neck as he walked home from football practice in Croxteth Park, Liverpool, in August 2007.
On Monday Panorama investigates the rise of armed teenage street gangs.
Reporter Graham Johnson returns to his Merseyside roots for this investigation to discover how ingrained the culture of guns and violence is in parts of Britain.
Though small in number, Panorama sees how teenage gangs and their turf wars devastate whole communities and meets the parents of teenagers who are being dragged into gang culture.
Rhys was shot dead in August 2007
The film speaks to former gangsters, shocked by the new levels of casual violence, including one who is trying to turn youngsters away from guns.
It follows the latest police efforts to stem the gun culture, going out on patrol with Merseyside Police's elite anti-gun and gangs unit - the Matrix Squad.
And, after weeks on the ground, the programme comes face to face with the young gunmen themselves.
Panorama: Young Gunmen will be on BBC One at 7.30pm on Monday 30 June 2008.