Christchurch Police won't say whether the Port Hills fire is being treated as suspicious, but confirmed they're collecting evidence and have spoken with several people as part of their investigation.
More than 100 weary firefighters and volunteers are still on the ground on the seventh long day of working on the blaze.
It's hard toil getting into where the fire continues to burn.
But through the charred remains, the remaining crews are a shining light.
"People at the lights, giving you a thumbs up, it's pretty cool," one firefighter told Newshub.
But the work is hot, and hard, and long.
"The guys are working solid 12-hour days," another said.
Many are volunteers from around the country, who have jobs that have taken a back seat.
"It's disrupted my work week and my employer has been really good," a third firefighter said.
Day, after day, after day, and sometimes all night.
"The emotional strain and that mental strain is very real for a lot of people on that fire ground," said Akaroa volunteer Ollie Rutland-Sims.
"Leaving the wife at home, yeah that's pretty hard. She doesn't like me heading away, not knowing when I'm gonna come back," another firefighter added.
They are in an ongoing hunt for hotspots, and on Tuesday morning there were still 50 left.
"They are down very deep. Crews have just found a few, so they're exposing them. [We're] hopefully getting a few helicopters in there shortly to deal with those," said sector supervisor Gordon Munn.
Some rain fell at both Waikari and Port Hills last night, which helps, but also hinders.
"It's quite a lot more hazardous for both our vehicles and especially our ground crew to walk through," said Rutland-Sims.
Police have now received several pieces of evidence, including photos and videos mostly from nearby residents, to help them determine the cause of the fire.
And police aren't ruling out that it was deliberately lit.
"We're certainly conducting an investigation which will consider all those possibilities," said Senior Sergeant Roy Appley.
Tellingly, with this message.
"This is the sort of thing that doesn't need to happen and unfortunately offenders very rarely think about the impact that this is going to have on the community," Snr Sgt Appley said.
"And sadly, sometimes may even get some kick out of doing this."
These hard-working crews though still get a kick out of doing their bit - and getting fed.
"[We] finished last night, the Army put on this feed - it was just amazing," said one firefighter.
Or even a snack on the job?
"Better not eat that on camera! A classic huhu grub. It's a good little extra bit of protein, your little snack in between breaks," another said.
