Lynette White's body was found with more than 50 stab wounds

They had been questioned on suspicion of false imprisonment, conspiracy to pervert the course of justice and misconduct in public office.

The four men and one woman were first arrested and released on Wednesday, then questioned again on Thursday.

Three men jailed for the murder in 1990 later had their convictions quashed.

In 2003, Jeffrey Gafoor was imprisoned for life.

The 20-year-old prostitute died after being stabbed 50 times at her flat in the city's Butetown area on Valentine's Day.

Steven Miller, Yusef Abdullahi and Tony Paris - who became known as the Cardiff Three - were jailed for life in 1990 for Miss White's murder. Their convictions were overturned two years later at the Court of Appeal.

Four of the officers who were arrested early on Wednesday were detective constables at the time of the original investigation.

DNA evidence that convicted Jeffrey Gafoor was at the murder scene

The fifth officer was a uniformed inspector, police said.

They were questioned and released on police bail.

A South Wales Police spokesman said the five had answered their bail and were being questioned at Swansea Police Station on Thursday.

The new inquiry into the prostitute's death on Valentine's Day 1988 was opened by South Wales Police in 2000.