Lynette White, 20, was murdered on 14 February 1988

Two of them answered bail on Friday and were back in custody for further questioning, South Wales Police said.

The three had been bailed on suspicion of conspiracy to pervert the course of justice, misconduct in a public office and false imprisonment.

The inquiry is into the original police investigation of the 1988 murder.

Nine retired officers were arrested last month as part of the inquiry.

Convictions quashed

The new inquiry, which is being supervised by the Independent Police Complaints Commission (IPCC), was launched 20 months ago to establish what went wrong in the original investigation.

Three men jailed in 1990 for 20-year-old Lynette White's murder - Steven Miller, Yusef Abdullahi and Tony Parris - later had their convictions quashed at the Court of Appeal.

In 2003, Jeffrey Gafoor was imprisoned for life after admitting he stabbed the prostitute 50 times at her flat in the city's Butetown area.

On Thursday morning, three South Wales Police officers - one detective sergeant, one detective constable and one police constable - were arrested at their homes and were questioned in Swansea Central police station.

They were later released on police bail pending further inquiries.

Police said on Friday: "Two people, arrested yesterday in connection with the original inquiry into the 1988 murder of Lynette White, have answered to bail and are back in custody for further questioning today".

'Search for truth'

Thursday's arrests follow two previous series of arrests last month.

Five former police officers were questioned at first, followed by four more.

All were held for questioning in connection with identical alleged offences before their release.

Speaking about the investigation, South Wales Police assistant chief constable Stephen Cahill said: "We have made a commitment to this search for the truth and we remain steadfastly committed to seeing it through to its ultimate conclusion.