Former Knox Grammar headmaster Ian Paterson has been grilled over his handling of a former teacher who watched hard-core pornography with male students.
Dr Paterson appeared at a hearing of the Royal Commission into Institutional Responses to Child Abuse today, telling the commission he should have known about the abuse of boys in his care over a 30 year period between the 1970s and 1990s.
The commission heard evidence that former teacher Craig Treloar exposed students to images of bestiality and pedophilia, and was accused of asking boys to perform sexual acts of him, Fairfax Media reports.
Dr Paterson said he made a "silly mistake" when he failed to ask Treloar what type of material he showed, how many boys were involved, whether he had propositioned the boys or if it had happened before.
"We should have investigated it more, absolutely," he said.
"It was not a failure at the time."
Treloar was suspended for six months and returned in 1989. He had been at the school for 27 years when he was arrested in February 2009.
Later that year, Treloar was sentenced to two years in jail for assault offences dating back more than two decades.
Earlier Dr Paterson apologised to those who suffered abuse and for failing to provide "a safe and secure place" for his students.
"As headmaster, I am responsible for all that occurs during my headmastership", he said.
"I should have known and I should have stopped the events that led to the abuse and its tragic consequences for these boys in my care and their families."
Dr Paterson wrote glowing references for staff members who left under a cloud of abuse allegations, telling the commission it did not occur to him that he should be concerned they would teach at other schools.
One of the teachers was Damien Vance, a housemaster accused of groping a 15-year-old boy in a room under the school chapel.
Dr Paterson said he remembered that incident and told the boy it was a serious allegation and to go to the library to think about it.
When asked by counsel assisting the commission why he told the boy to do this, Dr Paterson said the boy "was known as a dramatical boy who could build up situations".
The boy came back to Dr Paterson and repeated the allegation, and Vance was asked to resign. His letter of resignation did not mention the reason.
Dr Paterson was asked by Vance for a reference in 1991, and he obliged with a "strong" one praising his skills. That reference allowed him to register with the Victorian Department of Education as a permanent teacher.
Dr Paterson said at the time he did not think of the effect it would have on other schools or their students.
He acknowledged he knew about some of the matters but did not have any knowledge of others.
The 81-year-old made an official statement before the commission began to hear evidence from him about his management of teachers who had abused students at Knox Grammar.
"Reading your statements, watching your stories unfold has been shocking and heart-rending," he said.
"My abject failure to provide for you a safe and secure place at Knox strikes at the very heart of a responsibility of a headmaster. I commend your courage in coming forward.
"Knowing that I was your headmaster when much of this abuse occurred is devastating.
"An apology for the hurt suffered by you and your families seems totally inadequate. Yet I do so with an awful feeling of uselessness in my heart.
"I accept that decisions I made were wrong. And that I failed to recognise and hence respond sufficiently to events that we now know were indicators of a sinister and much bigger picture.
"A picture of serious sexual abuse that would damage the lives of so many."