A retired senior detective says he is optimistic progress will be made in the re-opened investigation into the murder of a prostitute in 1988.

Former Detective Chief Superintendent Bill Hacking from Lancashire has been reviewing the original police investigation into the death Lynette White in Cardiff at the invitation of the South Wales force since last June.

South Wales Police Assistant Chief Constable Tony Rogers said Mr Hacking's involvement was part a comprehensive review of the whole case.

An independent group was asked last year to look at a review of the unsolved case, which took place in Cardiff's docklands 12 years ago.

The death of 21-year-old Lynette White resulted in three men being jailed for life and then later acquitted at the Court of Appeal after it was successfully argued that a gross miscarriage of justice had taken place.

No other persons have ever been convicted in connection with the crime, which took place in Butetown in 1988.

Detectives announced in June last year that new methods of DNA testing may help to track down Lynette White's killer.

Mr Hacking said: "It is a difficult and a very complex case but my thinking is that our recommendations will point to further action that needs to be taken.

"I am confident that we can identify further lines of enquiry and then there is a good chance that this will further the case to a degree and possibly lead to a successful conclusion."

Mr Hacking said he hopes to present a report of the case review to South Wales Police shortly.

Author Satish Sekar wrote a book about the case published last year and has joined the calls for the case to be reconsidered.

He said the police should re-investigate five suspects who were never eliminated from police enquiries.