Police are investigating two new grooming and sexual abuse cases involving paedophile head teacher Neil Foden.
North Wales Police said the allegations related to victims who were "children at the time of the offence".
Foden was jailed for 17 years in July after sexually abusing four girls over a four-year period.
The Crown Prosecution Service (CPS) said police had not been in contact regarding any new allegations.
Foden was head teacher at Ysgol Friars in Bangor, Gwynedd, and strategic head teacher at Ysgol Dyffryn Nantlle in Penygroes.
Former Ysgol Friars staff member Ana, not her real name, said she was worried facts related to the case were not being shared with authorities and "secrets" were "casting a shadow" over the school's future.
"There are people there (at the school) who have information... and the feeling I have is that they won’t come forward," she said.
Ana worked at the school for 20 years and Newyddion S4C has spoken to several current and former staff members who shared her feelings.
The North Wales Safeguarding Board is carrying out a child practice review to see what lessons can be learned.
But there are concerns the review is limited and there are calls for a public inquiry and independent review of the county council's processes.
Ana questioned how much detail the panel had been given about how the school was run.
Brian Jones, the school's newly appointed chair of governors, said the child practice review team had visited the school on "several occasions" and staff had been given the "opportunity to share concerns or information that may be of use to them".
Ana said the culture Foden created at Ysgol Friars was "suppressive, toxic, fearsome and bullying".
She said there were "many things that have happened at the school that needed to come out" and "there are some members of staff who know more than they are saying".
After the crimes came to light, Ana claimed there was not enough support for teachers and other school staff.
The morning after Foden's arrest, she said there was a special staff meeting.
"We were sent straight back to work after receiving the news and were expected to carry on, when in reality all we wanted was to get together and discuss what we had just heard.
"It was a horrible situation."
She said a counsellor was available, but said some found it difficult to ask for help and requests for appointments were not anonymous.
It is understood at least 10 teachers are on long-term absence from Ysgol Friars, with sources claiming there had been an average of 18 absences a day since October.
Mr Jones said: "155 individuals work at Ysgol Friars, and naturally each has been affected as a result of Neil Foden's horrific crimes."
He said the new governing body was "committed to doing their very best for the welfare of the school's pupils and staff".
Ana also criticised the council, Cyngor Gwynedd, for not taking control of the school after Foden was accused, saying it should have reacted "a lot sooner".
Recognising the difficulties faced by pupils and staff, the council said its education department had been working with the teaching staff, support staff and school governors to "restore and stabilise the situation for the benefit of all the school's pupils".
During Foden's trial, the court heard colleagues saw him go to his car with one of his victims and hug her.
A former pupil who claimed Foden groomed her for five years said teachers and other school staff saw her get into his car alone several times.
Ana said many in the school were aware some girls got "a lot of attention" from Foden.
"We knew as members of staff we were not supposed to carry children in our cars, so why was it different for Foden, and why didn't anyone question that?"
Ana said she felt able to speak about how Ysgol Friars was run after leaving the school.
She said: "Every day, I think about those young girls Foden abused."
Foden left the school in September 2023, but she said "secrets cast a shadow over the school".
"I would say that many senior staff have been moulded into how Foden wanted them to behave.
"This is bigger than Foden himself. He made sure he was surrounded by people who weren't going to question him."
She said the school needed a "clean slate".
Mr Jones said he could not comment on matters relating to staff, but "any allegation" brought to the board's attention would be dealt with in accordance with its policies.
The conclusion of the children's practice review, chaired by Jan Pickles, is due next spring and will be presented to the Welsh government, but there are concerns about the communication processes and "timeliness" of responses.
The Child Protection Panel said the review team would make direct contact with individuals should they need to meet or discuss anything further.
But some within the school community said they were worried about confidentiality and general awareness of the review process, with parents not given a direct line of communication with the North Wales Safeguarding Board.
A letter from the school in July said information should be sent to the head teacher or a member of staff "in whom you trust".
There has been no further correspondence with parents.
Some said they were "surprised" and felt information should be sent directly to the panel.
The school does not currently have a permanent head teacher, with David Healey, who was deputy under Foden, in interim charge since September 2023.
Mr Jones said the post had been advertised three times but so far it had "not been possible to make a permanent appointment" and arrangements to appoint a head teacher on a temporary basis were under way.
The council said recruiting a permanent head teacher had been "challenging" and a new approach was needed.
Mr Healy is understood to have applied for the permanent post, but was not successful.
The council said a formal "recovery plan" was to be implemented, saying it had "proactive steps in place" to review internal processes, including a barrister investigating events in 2019 referenced in the trial.
"We can ensure that we will not for a moment forget about the most important ones in this whole situation - the girls who should have been safe in their school, and that is why we are going through these processes and arrangements," it said.