The investigation into the unsolved murders of three family members during an arson attack in south Wales in 1995 is to be reviewed.

Diane Jones, 21, and her daughters Shauna, two, and 13-month-old Sarah Jane died when petrol poured under the front door of their home in the Gurnos Estate, Merthyr Tydfil was set alight.

Annette Hewins was cleared of the convictions

The killer of the family has remained a mystery after the convictions of two women connected with the crime were over-turned by a court of appeal.

South Wales Police announced on Monday plans for an independent advisory group to oversee the review led by team of retired detectives from Devon and Cornwall.

The five member advisory group, drawn from a variety of professional backgrounds, will offer experience and skill to the review team.

They include a pathologist, a teacher and a member of the retail trade.

Diane Jones, 21, died in 1995

The group were appointed by South Wales Police who are in the process of revisiting unsolved murder cases.

During the initial investigation into the Gurnos murders three local women - Donna Clarke, her aunt Annette Hewins and Denise Sullivan - were arrested in connection with the case.

Ms Clarke and Ms Hewins were cleared of murder but convicted of arson with intent to endanger life.

They were given sentences totalling 33 years in prison.

Denise Sullivan was convicted of perverting the course of justice and jailed for four years, which was reduced to three and a half years at an appeal.

Fire engulfed the house in the Gurnos Estate

But in February 1999, an appeal court freed Ms Hewins from her 13-year sentence after ruling there was insufficient evidence against her.

Donna Clarke's conviction was also quashed and she was freed in April 1999 from a 20-year sentence.

A spokesman for South Wales Police said: "The appointment of the Independent Advisory Group is in line with the South Wales Police commitment to carry out reviews of all outstanding unresolved murder cases in the force area, appointing independent members to monitor the progress of the review."