Several people had been coming and going from the property in those weeks, Brown claimed.
The early morning raid turned up jewellery, electronics, firearms, methamphetamine and other drugs.
Ngarino, 36, has been charged on several counts and will next appear in Whangārei District Court on February 18.
In an open email to the school community, Brown described the man who had stayed at her house for 18 months as a friend she had been supporting through health difficulties.
She said the arrangement had seemed to work well and she was shocked about the recent events.
''I love my job and am dedicated to Waipu Primary School.
''This is a personal matter and I do not wish it to affect the school in any way, shape or form. I can provide an assurance that I no longer have any connections to this person.''
Board of Trustees chair Catherine Munro reiterated it was a personal matter and the board understood the crimes did not directly involve Brown and occurred outside the school and the school year.
''We are working closely with the Ministry of Education and New Zealand School Trustees Association (NZTA) to ensure that we handle this matter in line with best practice, follow due process and ensure all matters are dealt with legally and within policy requirements,'' Munro said yesterday. She said the matter had seemed to have no ill effect on the school, or ''our wonderful students, who are back at school today excited about the first day.''