"And I want to understand, if any wrongdoing is found, how that was allowed to happen and how we go about ensuring it doesn't happen again," he said.
Erkkila also acknowledged "feedback from our school community that we haven't told you enough and that we haven't told you soon enough".
"As a board, we have legal obligations and for that reason it has been a difficult environment to navigate. But I also recognise the need to be open as possible with our school community is important."
He added that the investigations were still under way and the board "cannot and will not pre-determine that".
"But if it is deemed that workplace bullying has occurred, I want you to know that it will be addressed.
"I cannot and will not allow bullying of any kind in our workplace. Being on the receiving end of bullying behaviour is incredibly damaging to a person's mental health and it will not be tolerated, now or ever.
"If there has been or if there is still workplace bullying happening, we need to know so it can be stopped."
The update comes after WorkSafe confirmed yesterday it was making inquiries about "staff wellbeing" at the school amid the absence of Burden and Williams.
The pair left the school sometime towards the end of term one. "WorkSafe has been notified of concerns about staff wellbeing at St Peter's School and is making inquiries," a spokesperson said.
Shortly afterwards, an email was sent out to parents and caregivers confirming the investigation.
In it, Erkkila confirmed the board had begun an independent investigation following a meeting with WorkSafe staff.
"I want to assure you that the wellbeing of all of our school community – both students and staff – is of the utmost priority to us as a board, and that the day to day learning continues as normal."
Campus principal Julie Small addressed students yesterday morning as they were "understandably concerned about the speculation surrounding the school", the email said.
Small outlined the importance of being careful about what is said about people and that it is human nature to wonder and speculate when there were question marks over a situation.
"But it's also important that we are mindful of what we say and that we are respectful of people's privacy."
She assured students that their wellbeing was of the utmost importance and that their day to day activities would not be any different.
Operational matters were now in the hands of chief operating officer Rob Campbell, while teaching and learning matters would be looked after by campus principal Julie Small.
Parents spoken to by the Herald had initially found the development bizarre.
One parent said yesterday he was "shocked and bemused" by the pair's unexplained absence.
"It's an amazing school and the level of communication is amazing, you get a weekly newsletter and so for that [email] to come out on Monday, that was really odd."
However, another parent was supportive of Burden,
"The staff and parents that I know have all very much enjoyed working with Dale, and the heads of department that I have become close with.
"He has a big presence at the school and he's very engaging with the students.
"He's a very stand-up guy."
