Stephen Lawrence murder: Eltham witnesses 'never found'
At least four people who were nearby when Stephen Lawrence was murdered in south-east London in 1993 are still being sought, Scotland Yard has said.
Among those who have never come forward is a man who wore a distinctive green jacket with a large "V" symbol on it.
The man was walking towards the scene in Well Hall Road, Eltham, but has never been traced.
Gary Dobson, 37, and David Norris, 36, were jailed for life in 2012 after being found guilty of the attack.
A fresh appeal to find others who were involved is being made on the BBC's Crimewatch.
Officers believe up to six youths were responsible for the unprovoked racist stabbing.
"We have always known there were other people involved," said Det Ch Insp Clive Driscoll of the Metropolitan (Met) Police.
As well as the man in the green jacket, another man is being sought who ran from the Well Hall Road roundabout to the bus stop where Stephen, 18, was stabbed.
'Should be punished'
Two other potential witnesses got off a bus directly across the road from the killing, police said.
Stephen's mother, Doreen, told Crimewatch her son died "because these men decided they were going to take his life, and they should be punished for it".
"Twenty years on, people seem to think: 'Why should we worry about that.'
"But Stephen's life has meant so much, and he deserved to make sure all his killers have been caught."
Police faced criticism over their initial investigation into the attack and a public inquiry branded the force institutionally racist.
The Met's commissioner, Sir Bernard Hogan-Howe, admitted last week it had taken "too long" to secure convictions.
He has vowed to "catch the other people involved".
Crimewatch will be broadcast on Monday 29 April at 21:00 BST on BBC One.