Senior WorkSafe investigators have conceded they initially recommended against charging Whakaari White Island's owners over the eruption in 2019 which killed 22 people.
But something changed and the Buttle brothers were charged with failing to ensure the safety of tourists.
This week the brothers failed to get charges against them thrown out, but now it's emerged that the decision to charge them in the first place may well have been touch-and-go.
There were concerns there wasn't enough evidence.
"That was the conclusion yes," investigations manager Casey Broad told the court.
Broad, who's the only WorkSafe witness, recommended "no enforcement" to his boss just weeks before the one-year deadline for filing charges.
"That is the recommendation that I forwarded to Hayden Mander and then the review process of the investigation and the evidence acquired then began," Broad told the court on Friday.
The court's yet to hear what changed, and why the brothers were eventually charged.
Broad also recommended an independent investigation into WorkSafe's own role in the tragedy but he told the court that didn't happen.
"I spoke with that to Inspector Mander, I don't know where he took that to," he said.
Earlier the Buttles, as directors of Whakaari Management Limited, were given the opportunity in an interview recorded in 2020 with Broad to say whether they believed they owed a duty to the victims of the eruption.
"We're incredibly mindful of the tragedy and its effects and it's impacted us a lot in that regard," Andrew Buttle said.
His brother Peter added: "There is no way you can respond sensibly to the scale of that disaster."
However, in a statement read to the court on Friday Peter Buttle clarified "because they weren't volcanic experts and had no ability to monitor the island on a daily basis it had to devolve to the operators and GNS to work out what's safe and what isn't".
"It's not an adventure unless there's some risk," his statement read.
But as to what to do about it, he didn't know what the answer was.
