True crime Sheffield: How murder of 16-year-old boy gunned down in city park shocked city

But ironically, just a few years later, the youngster from the Democratic Republic of Congo was killed in what is believed to have been a feud between two rival postcode gangs. He was assassinated in what should have been his safe haven: a city hailed as one of the safest in the country.

Jonathan had said goodbye to his mum on that fateful night when she went to church, and she thought her beloved son was meeting up with a group of friends.

But despite the teenager’s family believing that he had wanted to become a church preacher, he was leading a secret life they knew nothing about. He was a gang member and was known to have carried a gun and a blade. He was known as Venemous.

Although nobody is behind bars for Jonathan’s murder, detectives revealed what they believed happened to him when they charged a suspect soon after the killing and he was prosecuted.

He stood trial twice, with the jury unable to reach a verdict after the first trial and finding him not guilty after a second.

The South Yorkshire Police murder investigation led to the discovery that Jonathan had been a member of the S3 gang operating in Burngreave and Pitsmoor at that time, and which had been at war with the S4 gang from the same area.

When Jonathan was shot dead at the Nottingham Cliff recreation ground in Burngreave, the gun used to kill him was shot from a distance of around 60ft away from the teen and his pals. A red laser device had been attached to the gun to pinpoint the target.

It later transpired that there had been another attempt to kill Jonathan earlier that day when shots had been fired at him as he visited a friend’s flat.

Detectives said they believed that Jonathan’s murderer did not act alone and was that the teen was killed as part of a pre-planned plot. Police chiefs said Jonathan was ‘targeted and ruthlessly killed’ in an ‘organised and planned attack’ and that officers would ‘relentlessly pursue’ those involved.

They said at the time that regardless of who pulled the trigger, all those there and aware of the planned attack were just as culpable and would face murder charges if identified. To this day, nobody else has ever been charged.

Forensic work established that the gun used to kill Jonathan had been used to fire at another S3 member's home two months earlier.

Detectives believe the teen was targeted in retaliation for a shooting at a house belonging to relatives of an S4 member the night before the murder.

In the two years before Jonathan’s murder, police compiled a dossier of 38 incidents involving the feuding gangs, and a number of firearms were seized.

There had been a series of stabbings, shootings and tit-for-tat attacks.

The murder is one of a number of unsolved cases on South Yorkshire Police’s books, with the force having a specialist review team which re-examines historic killings to look for potential new leads.