The hunt for the women who brought Covid-19 to Northland showed police accessing a system that automatically records number plate information at petrol stations.
The detail is included in the 700-page investigation file that was released after the Herald sought access to the police inquiry through the Official Information Act (OIA).
It shows police pulling out all stops in trying to track the women down and is an eye-opening insight into how a wide net can be thrown in the search for people wanted for questioning.
Included in that was making contact with the Auror system, which offers high-tech camera surveillance to commercial outlets like petrol stations and shopping malls.
The system allows petrol stations to identify vehicles that have driven off after not paying for petrol.
But the hunt for the women shows officers talking of carrying out "Auror checks" and then emailing the company to seek information.
In response, police received details showing the number plate of a car linked to the women at a BP petrol station in Whangārei.
Police headquarters pointed the Herald to its latest policy on Automatic Number Plate Recognition (ANPR) technology, saying it got information from three sources - ANPR cameras in some police vehicles, police static cameras, ANPR-capable cameras owned by other government agencies, and local councils.
From government sources, police policy said it had access to number plate information collected by Auror and SaferCities, which both operate large CCTV networks.
The Herald today revealed the 11-day lockdown in October 2021 was the result of "human error" after a government worker approved an application to cross the Auckland border that was meant to be declined.
That allowed the three women who received travel documents to head to Northland where one later tested positive for Covid-19 and all eventually contracted the disease.
Among the documents released was a summary of a police investigation into the women which found "no offence" and no "deception" in obtaining the travel documents.
Detective Inspector Aaron Proctor's summary of "Operation Hiking" quoted an email from the Ministry of Business, Innovation and Employment which said the travel documents were "issued in error by the Ministry of Social Development, (the error not being the fault of the applicant)".
Proctor wrote that "this matter was the subject of a large media profile after Winston Peters claimed the women were gang-connected and had travelled to Northland with the assistance of Mongrel Mob leader Harry Tam".
"Further releases in the media suggested they were also prostituting which heightened media attention to the case."
The police inquiry summary said: "The police investigation found no evidence to suggest that [the women] had any connection to Harry Tam, the Mongrel Mob or were involved in prostitution."
The OIA included copies of police officers' notebooks detailing plans for tracking their movements and gathering information which could have formed evidence if a prosecution went ahead.
It shows police obtained production orders to get phone and text data from mobile phone providers and banking records to help track people. They also pulled together information about cars linked to the women and sought to track movements through public and private databases to which police had access.
In an effort to track vehicles linked to the women, the documents show one police officer reported a vehicle as stolen so it would "ping" the system in case it was spotted by patrol cars or automated number plate recognition systems.
One notebook entry recorded how ANPR systems did pick up the licence plate and the car was subsequently stopped by police. Having done so, the "stolen" notification was removed from police systems.
Police inquiries showed that bank cards were used at 11 Northland businesses between October 2 and October 4. Toll cameras at the Puhoi tunnel picked up one of the cars linked to the women going north at 1.30pm on October 2 and returning at 9.40pm on October 6.
The documents showed there was a second car involved which returned to Auckland on October 8.
There were three business-related calls identified but "all became ill with Covid soon after travelling, spent time in their accommodation and returned to Auckland", Proctor wrote.
One of the women tested positive for Covid-19 on October 4 and again on October 6. Police noted she was unco-operative and would not detail where in Northland she had been.
Suggestions one or more of the women had attended a gang tangi - a prospect that caused concern given the potential for spreading Covid-19 - wasn't supported by evidence which included officers scouring Facebook for video taken at the service.
The file showed the women reluctantly dealt with police and, in one case at least, a lawyer called officers with concern a client might be incriminating herself.
The size of the file led to police seeking an extension of the usual 20 working days allowed in law for a response to an OIA request. We were told we could expect a response by May 6 yet it wasn't until 7.30pm on September 5 that the information was provided.
The OIA papers show the women - who had earlier been blamed for using "false information" to get travel permits - had no links to gangs and weren't sex workers, as had been suggested.