Suzy Lamplugh's brother wants police to investigate new evidence that her body was dumped in a canal days after she went missing in 1986.
Richard Lamplugh, 61, believes that information revealed in a new documentary could finally lead to the discovery of his sister's body.
He told the Mirror: "Even just to rule it out, it would be good to investigate. But if they found a body and it was Suze, then that would be very exciting."
A witness believed he saw prime suspect John Cannan dumping a large wheeled trunk into a canal in west London three days after Suzy disappeared.
The documentary contains testimony from Anne, a friend of the witness, Dave, who died in 2008. Anne says Dave told her he saw Cannan as he walked to work along a towpath in Brentford in July 1986.
Anne says: "He saw a man coming towards him carrying a heavy load on wheels. The man put his face down - he wasn't expecting to see anyone that early, it was five o'clock in the morning.
"But Dave had to pass him, and as he passed he got a good look at his face. A few seconds later, Dave heard a splash, looked around and the man was running with nothing in his hand."
© Channel 5Her brother Richard is calling for police to investigate the new evidence
Dave reported it to his local police station, but it did not get relayed to the Met.
When Cannan's picture was in the newspapers in 1989, ahead of his trial for the murder of Bristol woman Shirley Banks, Dave recognised him.
Anne says: "Dave said, 'That's the man I saw on the towpath." He reported it a further two times to Brentford police, but the information still failed to reach the Lamplugh investigation teams.
© SKYSuzy with her siblings
Jim Dickie, who was on the case in 2000, think it is "very, very feasible" Dave saw Cannan dump Suzy's body.
He says: "It would meet his pattern of behaviour. He likes to dump bodies near water."
Cannan was given three life sentences in July 1988 for murder and sex offences.
© SWNS.comJohn Cannan
Suzy disappeared just three days after he was freed from a prison hostel in west London in July 1986, after serving five years for rape.
Estate agent Suzy went to meet a mysterious Mr Kipper for a house viewing and was never seen again.
Richard and his sisters Tamsin and Lizzie still dream of finding Suzy, who was declared legally dead in 1993.
Richard said: "It would be nice to bury Suze where we chose to bury her, rather than where he chose to bury her."
*The Mystery of Suzy Lamplugh, Sky Crime, tomorrow, 9pm and 10pm.