Anti-terrorist police stormed Kim Dotcom's mansion to search for a "Doomsday" device the FBI feared would wipe out evidence of internet piracy around the world.
The High Court at Auckland heard yesterday, during a judicial review of the police raid, that they did not find one, then for an hour left a prime target with exactly the sort of device the FBI believed could be used to set off the deletion mechanism.
Thirty armed police stormed Dotcom's Auckland home by road and air to find the device in the FBI-inspired raid in January.
Almost 30 other officers followed to search for evidence using a warrant since ruled invalid.
The fate of evidence gathered is to be decided after a hearing this week in the High Court.
Dotcom's lawyer, Paul Davison, QC, lambasted police for a "disgraceful performance".
"What this comes down to is a woefully incompetent and inept performance by the New Zealand police at all stages and at all levels of this operation," he said. "Those responsible for planning are shown to be deficient in their judgment to a serious degree."
But Detective Inspector Grant Wormald, who oversaw the operation for the Organised and Financial Crime Agency, (Ofcanz), said the operation - part of a global raid on Dotcom's Megaupload filesharing company - was an example of the "thorough and professional execution of a search warrant".
Again, Mr Davison questioned police claims a helicopter gave a critical speed advantage to halt the destruction of evidence. The move led to the involvement of the special tactics group (STG) as the only police trained to operate from helicopters.
Mr Wormald said he was told by the FBI that Dotcom "carried a device with him to delete servers around the world". Earlier evidence stated no such device was ever found.
Mr Davison, who had called it a "Doomsday" device, was told the device could have been triggered in seconds from any computer, laptop or phone in the possession of about 20 people on the property.
The QC then quoted police evidence which showed one of the men facing extradition was left with his iPhone for almost an hour.
"The potential destruction device had been left in his pocket."
Mr Wormald replied: "It happens to be something that shouldn't have happened at the time."
The officer also denied that police instructions setting out the process for involving the £ were compulsory. The rules state that operations using the elite unit "must" be approved by the head of national operations, Assistant Commissioner Nick Perry. Instead, the operation was approved by Assistant Commissioner Malcolm Burgess - also the head of Ofcanz, the agency that wanted the £ involved.
Mr Wormald said the police manual gave officers "a jolly good steer" and police headquarters was a flexible environment.
Mr Davison asked about the people who watched the operation unfold on video from the North Shore policing centre on the day of the raid. The United States' most senior law enforcement officer for cyber crime, Jay Prabhu, was present with Mr Wormald and Crown Law Office staff watching a video feed.
Asked where the broadcast was from, Mr Wormald refused to say.
In response to a question from Chief High Court Judge Helen Winkelmann, Mr Wormald said he rejected the option of arresting Dotcom after he left a recording studio about 4.30am, saying: "We were trying to delay as long as we could them making a call to a lawyer."
After Dotcom was advised of his rights he could phone a lawyer.
"You give him a phone and he makes that phone call in private, the cat's out of the bag."