Reports emerged yesterday that the alleged offender had just flown into the country from India and had waited at the school for the victim to finish her exam before the alleged attack took place.
Witnesses spoke of hearing screaming and seeing the victims covered in blood, one of whom had allegedly been stabbed in the neck.
In a statement last night, Detective Senior Sergeant Paul Newman said the woman's body had been removed from the scene and a post-mortem examination was scheduled to get underway today.
"We are working through the process of formal identification and contacting her family.
"Once the proper processes have been carried out we will be able to release her name but, in the meantime, we urge media and friends to consider the families at the centre of this tragic event when reporting on it."
Police Northern Communications Centre Inspector Kerry Watson said a third person had suffered minor injuries and was in police custody last night.
"No other persons are being sought in relation to this incident," he said.
Criminal investigators and specialist staff were also being brought in to work on the investigation.
TVNZ's One News reported the fatal stabbing happened at an international school where the woman victim was sitting an exam.
Witness Joe Johar said he heard screaming.
"I see a guy who got stabbed in his neck and he was bleeding badly."
Taylors College foundation studies principal Lindsay Spedding, whose Karangahape Rd establishment is across the street from the premises where the alleged stabbing took place, said all he could see of the incident was "lots of police cars".
Earlier, Detective Senior Sergeant Newman said police were dealing with a lot of people at the incident scene.
"We're dealing with quite a lot of people in the building, there's a lot of people outside of the building - we're trying to establish what's actually gone on and who's played what role in the incident."
-Reporting by staff reporters and NZME. News Service