The family of a 21-year-old music producer shot dead in Clapham has appealed for help to find his killer on the 19th anniversary of the murder.
The Metropolitan Police on Wednesday re-appealed for information on the crime, for which nobody has ever been brought to justice.
Mr Forbes was a “proud” father-of-one and his partner was expecting their second child with a music career that was going “from strength to strength,” when he was killed.
In the early hours of December 7, 2003, he was on his way to play a new mixtape to his friend when he was shot in his mother’s car in a car park near his home in Daley Thompson Way and was rushed to hospital but died later the same morning.
His sister Erica Forbes said: “Although it was 19 years ago that Leon was taken from us, I remember it like yesterday. My memories are so vivid from that night - the smells, the sounds, the terror, the fear of that night when gunmen decided to come and take my brother’s life, leaving him to be found by his mother.”
The Met said Mr Forbes was with a friend in the car, a black Vauxhall Astra, when he received a phone call, which he quickly cancelled, and drove towards the exit of the car park.
Near the exit, a second car was stationary with its headlights on and a man was stood in front of it. As they drove by, shots were fired into the rear of the car, hitting Mr Forbes - causing him to slump over the steering wheel and crash into other cars.
Witnesses reported seeing two vehicles, a red car and a silver car, leaving the car park at speed shortly after the incident - one being described as a recently-released Saab.
Five people were arrested in connection with the murder in 2003 and 2004, but all were subsequently released with no further action being taken.
Ms Forbes continued: “The one thing I cannot get over is the constant memory of my mother and I, taking it in turns trying to give my brother CPR [cardiopulmonary resuscitation[ and willing him to breathe.
“On the December 7, 2003, our lives changed forever and I know it will never go back to how it was. My mother has now since passed and never got to fulfil her promise to Leon, to see those responsible brought to justice.
“This is often very painful and heartbreaking. I now have to fulfil that promise to her and Leon, I will continue to seek justice and one day face those responsible in court and ask them why.”
Mr Forbes’s mother Michelle, who was a probation officer and co-founded the pressure group Mothers Against Guns, died last year.
Ms Forbes added that her brother, who would be approaching his 41st birthday if he was still alive, was “young, ambitious, confident and outgoing,” and liked by people even if they had just met.
“As a family we appealing to those who may know who is responsible, any information you have, to come forward and speak the truth,” she said. “Some of you may even have children the same age Leon was at the time of his murder- 21 years old.”
Mr Forbes was a promising musician and his band reached the finals of the Mobo Unsung awards.
The police said in their appeal on Wednesday that they hoped people who had not come forward with evidence might now feel compelled to do so.
Detective chief inspector Amanda Greig said: “Leon was only 21 years old when he was brutally murdered and he had his whole life ahead of him. He was an up and coming music producer and his career was going from strength to strength.
“He was the proud father of a little girl and he could not wait to meet his second child – but sadly that opportunity was snatched away from him.”
Anyone with information is asked to call the Met’s specialist casework team on 020 8785 8267 or 101. Alternatively, call Crimestoppers anonymously on 0800 555 111,