Police investigating the murder 14 years ago of a Cardiff woman, a crime of which three men were wrongfully convicted in 1990, said they had identified the DNA of the man they believe to be directly involved in her death.

Lynette White's mutilated body was found in her flat in Butetown, Cardiff, on Valentine's Day in 1988. Three men – Yusef Abdullahi, Steve Miller and Tony Paris – were convicted of her murder in November 1990. But the Cardiff Three, as they became known, were released on appeal in 1992.

A reinvestigation of the murder was launched three years ago and has resulted in the DNA profile being obtained from the scene. Assistant Chief Constable Tony Rogers announced that police intended to screen about 5,000 people involved in the first investigation.

He said: "South Wales Police has broken new ground in forensic work which had yielded a number of DNA profiles, both male and female, that can be linked to the murder scene.

"One particular male profile is of significant interest to the investigating team. The male is believed to be directly involved in the murder."

Police said the man had already been contacted and arrangements were being made to take swabs for DNA testing. A team of 20 officers was working on the inquiry but Mr Rogers said more would be brought in if needed.

The new development came shortly after South Wales Police announced they had identified a prime suspect for the murders of three teenage girls 28 years ago.

Mr Rogers added: "South Wales Police has embarked on a review and reinvestigation – where appropriate – of all undetected and unresolved major crimes."