Conversations recorded between internet mogul Kim Dotcom and his three co-accused, discussing their fear of being caught and ways of creating "legitimate" spin-off companies, have been read out in court.
"At some point a judge will be convinced how evil we are ... We have to make ourselves invulnerable," Dotcom is quoted as saying in US evidence presented in Auckland District Court to have the four men extradited.
After more than three years of legal battles, including 10 postponements and two Supreme Court hearings, arguments in the Megaupload founder's US extradition case began on Thursday.
Opening the case for US authorities, Christine Gordon QC said the whole case could be boiled down to a single statement: "[They] were part of a conspiracy, they deliberately attracted copyright infringing material to their websites, deliberately preserved that material, deliberately took steps to profit from that material and made vast sums of money," she said.
She said the only thing novel about the case - contrary to the respondents' argument - was its scale.
Megaupload had deliberately used auditors to conceal copyright infringing material on the site and encouraged users to make multiple links to each illegal file to make them more difficult to take down, Ms Gordon said.
"If copyright holders would really know how big our business is, they would surely do something against it. They have no idea we are making millions in profit every month," co-accused Bram van der Kolk was quoted as saying.
Dubbed the "Mega Conspiracy" by the FBI, US authorities allege Dotcom and his associates - Mathias Ortmann, Finn Batato and van der Kolk - illegally made $US175 million from file storage website Megaupload and related sites.
Ms Gordon disputed arguments Megaupload was "like a post office" and not responsible for what its users sent through.
"In fact, one would shut down the post office if those who created and ran it had actual knowledge they are repeatedly shipping drugs and did nothing about it," she said.
She said another person arrested over the same "conspiracy" had already pleaded guilty in the US, and a judge there had deemed the case to be enough for a conviction.
If extradited and found guilty in the US, the four face charges that carry decades of jail time.
They include conspiracy to commit racketeering, conspiracy to commit money laundering, wire fraud and two kinds of criminal copyright infringement based on an FBI investigation going back to 2010.
Judge Nevin Dawson doesn't have to decide whether the four are guilty or not, only if they should be surrendered to the US to face charges there. The justice minister then makes a final decision on extradition.