On Thursday, former Collegiate headmaster Ian McKinnon told the court he did not remember getting a letter containing allegations Gibbs had abused a pupil.
The Crown suggested Mr Mckinnon had received the letter that alleged a pupil had been sexually abused by Mr Gibbs before he became headmaster.
Giving evidence by audio-visual link, Mr McKinnon said had that been the case he would have treated it seriously and notified the board and his deputies.
In 2006 he wrote a reference for Mr Gibbs at the same time the teacher faced charges relating to sexually abusing two boys in New Plymouth, RNZ reported.
He said he believed Mr Gibbs was defending the matter.
Under cross-examination, Mr McKinnon said he was disturbed when Mr Gibbs pleaded guilty and he would not write a reference for him today.
RNZ said Gibbs' lawyer, Annabel Maxwell-Scott, told the court the case was tricky.
She said the case's historical nature meant some witnesses had died and others had to rely on their memory.
Ms Maxwell-Scott said the abuse was said to have happened at a time there were no mobile phones, no computers and being gay was illegal and for Mr Gibbs to have done what he was accused of he would have risked everything.
She asked the complainant if he was ashamed and angry about being a homosexual and blamed her client.
The complainant said that was not the case.
He said it was hard to know how being forced to have sex with an adult for four and a half years had influenced his life.
He accused the school of turning a blind-eye to the sexual abuse.
The court also heard from two former students of Mr Gibbs who say he never acted inappropriately with them.
Yesterday Judge Richard McIlraith was to sum up the case for jurors before they retired to consider their verdicts.
