Since the news broke yesterday, much debate pivoted on ideas the man must have picked up Covid-19 either in prison, or after crossing the alert level border.
But this afternoon,health officials proposed another option - that he was infected after leaving prison in Auckland, and before arriving home.
Although the new theory seems to narrow the mystery, it's still not clear exactly when, or from whom, he contracted Covid-19.
"It's clear this person has been infected by someone involved in their transport to the bail address," Prime Minister Jacinda Arden said this afternoon.
"The final household member of the northern Hauraki house where the remand prisoner stayed has now been tested and results are pending," the Ministry of Health said.
"Our working hypothesis [is] the individual was infected in Auckland after leaving prison, rather than by someone in the local community where he was staying."
That could provide some relief to Corrections officers and to Covid modellers.
The Corrections Association was unaware of any other Covid-19 cases at Mt Eden or other prisons in recent weeks.
"I've not heard that anyone anywhere else in the prison estate has tested positive," Corrections Association national vice president Paul Dennehy said earlier this afternoon.
He said arriving prisoners at Mt Eden were all tested, then placed in a separation unit.
Dennehy understood this separation period lasted 14 days, and Corrections officers working with these prisoners wore full PPE.
After the prisoner was found to have Covid-19, some household contacts in the Kaiaua-Whakatīwai area tested positive.
These areas are south of the alert level boundary, and the new cases had raised concerns about the transmission of Covid-19 in the Waikato.
Prof Shaun Hendy said the better outcome for the country would be if the inmate contracted Covid-19 in a locked-down Auckland, rather than at the bail address.
The inmate went to Manukau District Court on Friday, was moved to Mt Eden prison, and tested positive for Covid-19. Photo / Google
Hendy, a physicist and Covid modeller, said the inmate potentially picked up coronavirus in Auckland on or just before September 8, and may have had a long incubation period.
If so, he could have been infectious on the weekend of September 11th and 12th, aligning with moments of transmission and recent positive test results for his contacts.
Hendy said the Delta variant typically had a high "household attack rate".
This meant household contacts generally had a high chance of contracting Covid-19 from someone with the virus.
The speed of viral spread could depend on residential layouts. Contacts on a farm but in different buildings would slow the household attack rate.
Hendy said it could take days, but probably 24-48 hours, before testing of the man's contacts helped illuminate where the Kaiaua-Whakatīwai cases originated.
Hendy urged anyone in the region with symptoms to get tested.
Prisoner's journey
The prisoner was released on electronically-monitored bail from Mt Eden Prison on September 8 to a Tikapa Moana/Firth of Thames residence.
The case also raised concerns about why some people who were in court when the inmate appeared were not alerted sooner.
This afternoon, officials said people in Courtroom 4 on Friday were adhering to physical distancing.
Multiple lawyers contacted the Herald with frustrations about the time taken to get information to people who were in the courtroom.
Justice and health officials have still not confirmed if everybody present in court with the prisoner had been identified and contacted.
The prisoner in Mt Eden is scheduled to appear again before the court later this week. The Herald has approached officials asking how this hearing will be conducted.
The Government at 4pm today announced Auckland would move to level 3 at 11.59pm on Tuesday.
