Following Kadeem's death Derbyshire Police prioritised tackling gang culture
An insulting comment about a rival gang member's mother was the trigger for the murder of 15-year-old Kadeem Blackwood, as a feud between two Derbyshire teenagers escalated out of control.
Kadeem was armed with a kitchen knife when he went to Caxton Street recreation ground in Derby for a grudge fight with Michael-Paul Hamblett-Sewell last November.
But Hamblett-Sewell - the self-styled "general" of the A1 Crew - had decided he was ready to kill over the issue of disrespect.
He had already ordered a lower-ranked gang member, Callum Campbell, to shoot Kadeem and as he pulled out his knife the teenager was shot in the chest with a pellet from a sawn-off shotgun.
Murder increased tensions
The following day, as friends paid tribute to 'Snipez', short for 'Sniper', details began to emerge of the violent street-gang culture that had taken hold in parts of Derby.
It emerged that gang members had started routinely carrying guns and knives as turf wars and drug rackets escalated.
A video posted on the internet showed Kadeem and fellow members of the Younger Browning Circle Terrorists (YBCT) wearing black bandanas issuing a warning to a rival gang not to step on their "turf" at Caxton Park - six months before Kadeem was shot there.
As the extent of the problem became clear community leaders organised protest marches against gang culture.
Realising the murder had increased tensions and fearing "tit-for-tat" revenge attacks, police brought in gang mediators to try to calm the situation.
But quick action had already led to the arrest of Hamblett-Sewell, just the day after the murder, and Campbell three days later.
By the following month a total of 15 people had been arrested over the murder.
Hamblett-Sewell and Campbell were charged with murder and two others were charged with assisting an offender.
Several members of the A1 Crew have also subsequently been jailed over firearms offences.
The death of Kadeem shocked the city and Derby's Community Safety Partnership made tackling gang culture its top priority.
A specialist gangs unit was created and in March a hotline was set up for people to pass on information about gang activity and crime.
The following month detectives announced plans to train teachers and social workers to spot children involved in gangs, after it emerged hundreds of schoolchildren had claimed allegiance to the A1 Crew.
The city's first gun and knife amnesty was hailed a success in July after 72 guns and 200 knives were handed in, as well as machetes, crossbows and meat cleavers.
Now police say they hope Kadeem's death and the trial of Hamblett-Sewell will act as a "wake-up call" to people involved in gangs.
Assistant Chief Constable Peter Goodman said: "The message people are starting to pick up is at worst you're likely to die or at best you will probably go to prison for a very long time."