Police wrapped up their scene examination at Zion Wildlife Gardens near Whangarei on Thursday, after a fatal tiger attack.
Inspector Paul Dimery says the site of the mauling, on Wednesday, has been mapped and photographed, and staff have been interviewed.
He says by their accounts the rare Bengal white male tiger attacked senior keeper Dalu Mncube as he was cleaning its enclosure, leaving him with unsurvivable injuries.
Inspector Dimery says Zion staff shot the tiger so they could retrieve Mr Mncube's body, because it would otherwise have been too dangerous for them to enter the enclosure.
He says police are working closely with Occupational Safety and Health inspectors.
Labour Department chief adviser of occupational health, Dr Geraint Emrys, says its inquiries could take up to six months.
The attack was witnessed by a group of eight tourists, understood to be English and French.
Shaken staff and the tourists have been given counselling and help from Victim Support.
The wildlife park is closed until further notice.
There are calls for standards to be implemented when caring for big cats following the death of Mr Mncube, an experienced keeper from Zimbabwe.
The tiger is believed to be the same animal which attacked a keeper earlier this year.
The Ministry of Agriculture and Fisheries is refusing to comment on or answer questions about the attraction's safety.
MAF cancelled the licence of the Zion founder, Craig Busch, who is known as the Lion Man, last year, citing safety concerns.
But it subsequently approved the present manager Glen Holland as the operator, and said its concerns had been addressed.
Sources within MAF have told Radio New Zealand of concerns that the dysfunctional management of the park posed serious risks.
Other parks concerns
Ian Adams, the Animal Collection Manager at Orana Wildlife Park in Christchurch, says he believes keepers at Zion get too close.
Mr Adams says a standard needs to be brought in so people are not putting themselves at risk so much.
He says the tiger did nothing wrong, as it is a predatory animal and someone was in its enclosure.
Close encounters "inappropriate"
Former Wellington zoo-keeper Bob Bennett is also critical of Zion's hands-on approach.
Mr Bennett was attacked by two lions in 2006 after they were accidentally let into their enclosure while he was still inside.
He says petting and handling big cats in the fashion that Zion does is not appropriate.
Death tragic, says Lion Man
Craig Busch, who founded the wildlife park and starred on television's Lion Man series, says Mr Mncube's death is tragic.
Mr Busch has not worked with the animals since he was sacked from his job as park manager by his mother, Patricia Busch, in a bitter financial dispute.
However, he says he knew Mr Mncube well and his death is a terrible personal blow.
Mr Busch is challenging his dismissal through the Employment Relations Authority and his lawyer says one of the issues raised is safety.
The hearing was adjourned on Wednesday.