Winston Peters has shocked and appalled New Zealanders with a false claim the office of former prime minister Jacinda Ardern had advance warning of the Christchurch mosques massacre, but covered it up.
The 2019 attack, in which 51 worshippers were killed by Australian terrorist Brenton Tarrant, is the subject of a coronial inquest which began this week in Christchurch.
On Wednesday, the inquest reviewed an email sent by Tarrant to a range of locations - including Ms Ardern's office - just a few minutes before he began his crimes.
A parliamentary staffer, granted name suppression by the inquest, reviewed the email and called police at roughly the same time Tarrant arrived at Al Noor Mosque.
A transcript of that conversation was tabled at the inquest, in which the staffer denied downplaying the seriousness of the threat, even as he called Tarrant a "just a nutter" and a "crank".
"I had no idea at the time it was going to lead to what it sadly led to," he told the inquest.
"I don't know what more we could have done."
The email to Ms Ardern's office has been canvassed many times before, including by Ms Ardern herself in a press conference on the day after the attack on March 15, 2019.
However, Mr Peters, deputy prime minister at the time, seized on the evidence to erroneously claim Kiwis had been kept in the dark.
"We waited until today to find out, for the first time, that the Prime Minister's Office received information about the March 15 terrorist attack before the massacre took place," he posted on social media on Tuesday night.
"Jacinda Ardern should be called to the hearing and asked to explain this appalling lack of transparency to the New Zealand public - let alone to the deputy prime minister and government coalition partner.
"This was a crisis event. To keep this basic information hidden is not only unacceptable it is now clearly indicative of how that office worked."
Mr Peters showed no sign of remorse in a follow-up post at 11pm on Tuesday, calling critics "political apologists and feckless media".
"To excuse it because it was known at a 'public press conference' the next day, instead of information that should've been shared with the deputy prime minister and coalition partner the day before, is as bizarre as it is biased," he said.
Deputy Prime Minister Carmel Sepuloni said Mr Peters should apologise after his "bizarre" claims, while a spokesman for Ms Ardern said Mr Peters was "completely inaccurate".
"Mr Peters should remove the tweet and post a correction," her spokesman said.
The intervention comes at a delicate time for survivors and families as they revisit New Zealand's worst modern-day mass shooting in painful detail during the seven-week inquest.
It also comes as Mr Peters, 78, is in government formation talks after the October 14 election.
Mr Peters' New Zealand First party - which in the past has railed against Islamic immigration - is in coalition negotiations with the centre-right National and right-wing ACT parties after Kiwis voted to change the government.
Mr Peters opted to form government with Labour in 2017 but has since washed his hands of Ms Ardern and other party leaders after exiting parliament in 2020.
In the 2023 campaign, Mr Peters said he would only work with the parties of the right, though both National and ACT campaigned against working with him, saying they would reluctantly deal with the veteran if their majority depended on it.
The three parties are waiting for the conclusion of the vote count on November 3 to confirm their coalition.
Incoming Prime Minister Chris Luxon has declined to comment on those talks, or Mr Peters' comments on the massacre.
