Who is Mr Kipper?
Suzy Lamplugh, an estate agent, disappeared on 28 July 1986, after going to meet a client - named as Mr Kipper - who was never traced.
No-one has ever been charged in connection with Miss Lamplugh's disappearance, but in 2002 police named the convicted killer John Cannan as their prime suspect.
Cannan, who is serving a 35-year prison sentence for the 1989 murder of newly-wed Bristol woman Shirley Banks, has denied the allegation.