THE senior detective hunting the killer of a 16-year-old schoolboy has revealed that none of the people who were with him on the night he died have willingly stepped forward as witnesses.

Up to 40 youngsters were involved in the terrifying street brawl that led to Ben Hitchock being stabbed to death in Beckenham.

The officer in charge of tracking down those responsible said 22 youths had been arrested so far in connection with the investigation.

Det Ch Insp Dave Garwood said: "Three months into this we have a total of 25 people on bail. The frustrating thing is that people who should have come to us on the first day are waiting for us to find them."

He said: "It's no good lighting a candle for Ben if you know something and you're sitting on that. We are going to find out who these people are. Things are falling into place."

Ben, who lived in Penge, was stabbed to death in Southend Road, Beckenham, during a street fight believed to have started after the group he was with was turned away from a house party in nearby Copers Cope Road, on June 23.

His grieving mother, Leigh, has hit out at the "wall of silence" that has prevented police from catching her son's killer.

She visited his school, Kelsey Park Sports College, in Manor Way, Beckenham, on Thursday to plant a tree in Ben's memory.

The olive tree outside the school entrance is a sign of peace.

Ben's younger brother and more than 50 friends and school staff looked on as his mother choked back tears while reading a tribute.

She said: "We will watch this tree grow, mature and reach its full potential as we would have watched Ben. The enduring memory of Ben was his cheeky grin, his infectious laugh that made us all laugh although we often had no idea why, his kind heart, love and respect, his great sense of humour and his determination to succeed in all he set out to do."

Leigh added: "Ben was often seen pedalling furiously on the very smallest of bikes, his long legs almost touching his chin, in order to get home on time. He will be remembered with love as the biggest boy on the smallest bike with the biggest grin. Ben had everything to live for and I know he would have continued to make us proud. This olive tree is a symbol of his strength and beauty."