BBC's Geeta Guru-Murthy: "This case has revealed a degree of continued tension and mistrust"

The pair assaulted and racially abused Ricky and a group of his friends shortly before he disappeared in Kingston-upon-Thames in October 1997.

Hours later the 20-year-old Brunel University student drowned in the river - his body was not discovered for a week.

An open verdict on his death was returned on Monday. Coroner Dr John Burton said there was not enough evidence to establish how Ricky died.

But police are anxious to establish a cause amid accusations that their investigations were inadequate, and the belief of Ricky's family that he was murdered in a racist attack.

'Separate incident'

Det Chief Insp Sue Hill appealed for the two white youths to come forward because they might have information about the student's death.

Campaigners attack police handling of case

She said: "We know that there was a separate incident and then Ricky wandered away.

"Those two boys have been branded as racist murderers but what we are saying is come and talk to us, you may have information that could help.

"Please come forward for the sake of Mr and Mrs Reel.

"At the end of the day Mr and Mrs Reel want to know how that lovely young boy of theirs died. My heartfelt sympathy goes out to them."

The BBC's Penny Wrout: "The family sat through a six day ordeal"

Police had originally thought his death was a tragic accident.

But the case was reopened after a campaign by supporters.

The Police Complaints Authority said earlier this year that the initial investigation into his death was "flawed" and found three officers guilty of neglect of duty in connection with the case.

Sukhdev Reel: "Verdict just a start"

Ricky's mother Sukhdev Reel, who contends that her son was murdered, said the open verdict was just "a start" in finding out how he died.

"It's better than what the police tried to prove," she told the BBC.

"If they had held a thorough investigation in the first place there would have been no need for a second investigation using further resources."

John Grieve, of the Race and Violent Crime Task Force, said he agreed with the verdict.