Clive Hally, 67, was arrested earlier this year on suspicion of indecent assault, following allegations of historical child sexual abuse at Brynteg Comprehensive School, Bridgend.
His victims said they were made to perform sex acts on the teacher and receive them on school grounds.
The retired teacher was on police bail, when he was found dead on May 18.
He is thought to have killed himself before a charging decision was taken.
His body was found floating on the edge of the Cwmwernderi reservoir near Maesteg. Police say there were no suspicious circumstances.
Mr Hally, from Maesteg, taught art at Brynteg for 36 years, from 1975 until 2011.
Two of his victims, now aged 48 and 50, claimed he sexually abused them on school premises in the 1980s, one when he was aged 13.
The other victim said he was assaulted multiple times, from the age of 15.
Mike – who’s name has been changed to protect his identity – alleged to the BBC he was abused in a locked photography darkroom, an art storeroom, disused toilets and elsewhere at Brynteg, after school and during school holidays, from when he was in Year 10, until after he left school at A-level.
He was made to perform sex acts on the teacher and receive them.
“He’d take me by the hand we’d go into the storeroom and it would be maybe 5 or 5:30, something like that, and I’d end up getting undressed…and it’s odd, I can’t remember Clive saying anything,” said Mike, now 48.
“I think he would undress me. I don’t remember me wanting to get undressed. I think he did it to me.
“Lots of awful things would happen. I didn’t want to touch him.
“So I’d be in the storeroom and I’d focus on, like a stapler or a door handle or a jug of pencils or something. It’s a crazy thing – I didn’t want to disappoint.
“But also, I didn’t know how to get out of there – I didn’t want to do any of this.
“But you’re in this position and you don’t know what to do.
“I can remember being naked and lying on a wooden counter, a sort of desk, where he kept lots of paper. I just wanted it to end really quickly.”
David, who’s now 50, accused Mr Hally of touching him sexually in an incident in the art store room when he was 13.
He said he had endured years of unwanted and inappropriate physical attention – including hugs and kisses, and they were once interrupted by a supply teacher.
“People must have known that things were going on because we were interrupted and I know I’m not the only person,” said David.
“He was at this school from 1970 something to 2011, so there’s a big period there where he had the opportunity to do things.
“There are more kids out there who’ve been abused, that’s a definite, an absolute definite”
Clive Hally victim
“I’ve learned that some staff did have concerns about the way that he conducted himself, to the point where they knew he would be one-to-one with boys in his art room and he’d lock the door.
“The bottom line is the man was a paedophile. It’s unbelievable really, when you think about it. That word should be associated with that man, as that’s what he was.
“There are more kids out there who’ve been abused, that’s a definite, an absolute definite.
“Paedophiles don’t stop abusing children, so for years in that school there was an active paedophile, and people should know.”
The men have heard a group of teachers did once raise concerns later in Mr Hally’s career about him spending time alone with boys in the art room, but it is unclear what action was taken.
A woman who was a pupil at Brynteg in the early 1980s told Daily Star Online: “He did have his favourites and lads who stayed after school or spent time in his class during lunch.
“I just thought because they were good at art that they had ‘special attention’.
“It’s very say to hear that was what was gong on and these boys were subjected to this abuse.
“I worked in the school later on in life and found him quite charismatic, but he did have a big temper on him which I saw as a pupil and a member of staff years later.”
South Wales Police said the two victims in the investigation have been updated and offered support by specially trained officers.
“South Wales Police takes all reports of sexual assault seriously and urges victims to come forward to report it, regardless of when it happened, safe in the knowledge that they will be treated with respect and dignity and that their allegation will be fully investigated,” said a police official.
Haley’s inquest will be held in November, with a police investigation into the allegations is ongoing and an independent investigation will be conducted.
Daily Star Online has approached Brynteg Comprehensive School for comment.
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