A senior policeman is under pressure to explain his decision not to prosecute a school principal.
Inspector Les Paterson of North Shore Police investigated former Kristin School headmaster Peter Clague after the principal's ex-wife, Jeanne Jackman, accused him of assault.
Clague is now subject to a private prosecution on the claim. Earlier, police said the decision not to prosecute was made because Jackman delayed reporting the incident
Now Paterson has been summonsed to appear as a witness in the private prosecution case, and had to provide an affidavit explaining his actions.
A police source said police were reviewing Paterson's decision.
This week in Auckland, Judge Pippa Sinclair declined to throw out the assault charge.
Clague's unsuccessful application to have the charge rejected means if the case ends up before a jury he will have to return to New Zealand. Clague started his new job at Bromsgrove School in Worcestershire this month.
In an affidavit, he alleged the couple argued and Jackman became "hysterical". He alleges they fell backwards as he stumbled after putting his hands on her shoulders, trying to calm her. Jackman alleged she was pushed. The couple separated in April 2012.