POLICE remain committed to pursuing all viable lines of inquiry on the Stephen Lawrence case, officers said.

The investigation will be featured on the BBC's Crimewatch programme tonight, a week after the 20th anniversary of the racist attack.

Detective Chief Inspector Clive Driscoll will take viewers back to the scene in Eltham, south-east London, and run them through the events of that night in an appeal to witnesses who it is believed have never come forward. The programme also features an interview with Stephen's mother, Doreen, who talks about why it remains so important for any outstanding witnesses to come forward.

Scotland Yard said: "Despite securing two convictions in this case, the investigation remains open and officers believe there were individuals in the vicinity of the murder who have never come forward."

These include two men who got off a bus at the stop opposite where Stephen was attacked, a man who ran from the area of Well Hall Road roundabout to the bus stop on the same side of Well Hall Road as the attack, a man who was walking on the east side of Well Hall, opposite the Coronet cinema, wearing a distinctive green jacket with a large "V", and anyone else in the general vicinity, such as those outside the cinema and on buses.

On April 22, 1993, aspiring architect Stephen was stabbed to death by a group of up to six white youths in an unprovoked racist attack as he waited at a bus stop with a friend.

In January 2012, Gary Dobson and David Norris were found guilty of being involved in the attack and sentenced to life imprisonment, after a forensic review found significant new evidence on clothing seized from their homes.