Although much of the initial behaviour she claims to have witnessed was "subtle", she said she believed the situation was widely known and even teachers at other schools discussed it with her.
"He showed interest in lots of girls, like he would be like flirty but not like anything you could report. Just kind of creepy.
"He was just so gross, just so inappropriate, even just the way he acted around students it wasn't like overtly inappropriate it was just very subtle and every day."
By sixth form (Year 12), she said his special attention on her classmate had become "really obvious", but they had no proof of what was occurring.
"I didn't ask her, are you having a relationship with our music teacher. We just didn't talk about it.
"It was just this weird thing that no body talked about."
However, during an overseas school trip she alleged his behaviour was on "full display" and he would do things like "lurk" outside of her classmate's room and walk her to the school bus.
Eventually the woman and another classmate went to a senior leader and accused him of favouring the other young woman and being in an inappropriate relationship with her.
The school's current principal, Lorraine Pound, was asked what action was taken after the complaints and whether the situation was elevated beyond the school, but she said they have no records of any complaints.
However, following the meeting, the former student said he left the school suddenly.
"He was pretty much gone right away, because I don't remember feeling scared to be in the class thinking he knew it was us.
"It's just weird that they wouldn't even announce it. Like if a teacher leaves after all these years wouldn't you announce [it]?
"You don't just leave a really good job without a fight."
The Spinoff asked Adlam about an alleged incident at Epsom Girls' Grammar in 1999 which arose during the course of their reporting - Adlam confirmed that he was questioned in regards to impropriety while he was a music teacher at the school but the investigation found insufficient evidence to proceed.
Another former student confirmed complaints about his behaviour were raised at Epsom Girls' and said Adlam had established a "pattern" of entering inappropriate relationships with students.
"He was a sleaze, he was pretty sleazy, we'd always known it. He was always saying inappropriate things to students."
She believed multiple complaints were made about him at the school.
While Sarah said she was relieved he was gone, she was frustrated there weren't better reporting systems in place by adults and that they weren't informed of the status of their complaint.
"They didn't come back to us about anything. It was just [not talked about] and I and I guess you know, the same thing happened St Cuths with James Tibbles because that happened when we were in high school."
The Herald has tried to approach Adlam several times about these allegations but has been unable to get a response.
Two weeks ago Trinity College London - a leading international exam board and independent education charity - confirmed to the Herald that Adlam's contract with it was being suspended while they undertake their own inquiries.
•Names have been changed to protect their identities.
Sexual harm - Where to get help
If it's an emergency and you feel that you or someone else is at risk, call 111.
If you've ever experienced sexual assault or abuse and need to talk to someone, contact Safe to Talk confidentially, any time 24/7:
• Call 0800 044 334
• Text 4334
• Email support@safetotalk.nz
Alternatively contact your local police station - click here for a list.
If you have been sexually assaulted, remember it's not your fault.
