John Owen killed himself last October

Seven of Owen's alleged victims - five men and two women - are due to give evidence to the Clywch inquiry, at the University of Glamorgan in Treforest near Cardiff.

The hearing - which resumed on Tuesday following an Easter break - has heard about the letter which ended his teaching career.

In it, a mother described him as "a little Hitler" whose drama lessons were "virtually pornographic".

Mr Owen taught drama at Ysgol Gyfun Rhydfelen until he resigned in 1991.

That resignation followed the letter in which the mother described how her bright, successful daughter had become depressed and suicidal while he taught her.

She made specific allegations about the sexual content of his lessons, saying boys were asked to undress and explicit sexual overtones had been introduced into almost every aspect of a play.

Owen taught drama at Ysgol Gyfun Rhydfelen

Counsel to the inquiry Nicholas Cooke QC said the letter led to a police inquiry and an investigation by the department of education.

But police decided not to prosecute and after Mr Owen's resignation the investigation was more or less abandoned.

Mr Cooke told the Children's Commissioner Peter Clarke that one recommendation he should consider was that serious allegations should be fully investigated - even after a teacher resigns - so that abusers could not simply get a job somewhere else.

That recommendation coincides with a BBC Wales investigation about concerns that Mr Clarke may have underestimated the volume of work involved.

The campaign group Children in Wales told the Welsh language current affairs programme Taro Naw it feared the inquiry would not be completed within three months as Mr Clarke had hoped.

Peter Clarke will examine issues involved

The inquiry into John Owen is the first inquiry to be held by Mr Clarke since his appointment in spring 2001, which followed the Waterhouse report into widespread abuse at children's homes in north Wales.

On its opening in March, he said it was intended to be investigative rather than judgemental, and would not be concerned with civil or criminal liability.

After Mr Owen, from Tylorstown in the Rhondda, quit amid complaints about his teaching methods, he wrote Pam Fi Duw? as a novel, which later became a popular Welsh-language television drama series.

Last year, four of Owen's former pupils came forward with abuse allegations dating back to the 1970s.

He was charged with five counts of indecency with boys between 1974 and 1991.

In October 2001, he failed to appear at Cardiff Crown Court for a pre-trial hearing and a warrant was issued for his arrest.

The next day he was found dead in a caravan at Trecco Bay, Porthcawl on the south Wales coast.

An inquest at Pontypridd in December heard how Owen killed himself with an overdose of morphine.

Coroner Phillip Walters said he was satisfied it was the abuse allegations which led him to commit suicide.

The hearing is due to continue until June with a report being published by the end of the year.