He does not have to decide whether they are guilty or even likely guilty - the threshold is lower.
If, on the face of it, he rules there is some merit in the US government's charges and a case to answer, on the face of it, the quartet will be sent overseas.
However, should that be the case, an appeal of the District Court's decision would not be a surprise since the last three years has been dominated by legal wrangling in all New Zealand's jurisdictions.
The Crown - acting for the US government - began by labelling it a "simple scheme of fraud".
Its case is that Megaupload was set up to operate like a large hard drive connected to the internet.
Users would upload content, the vast majority of which breached copyright laws, and share it with other members, Crown lawyer Christine Gordon said.
At its peak the site was attracting 50 million unique daily visitors, accounting for 4 per cent of all internet traffic.
It made US$25 million from advertisers, but Ms Gordon said its main source of revenue was small fees paid by the huge numbers of users, which totalled more than US$150 million.
Ms Gordon said some of those proceeds were used to reward people who were responsible for directing the most traffic to the site, while publicly Dotcom tried to convince copyright holders they were doing all they could to remove the offending material.
Dozens of conversations between the four men were cited by the Crown in a bid to convince the court they were conscious of the illegality of their actions.
"If copyright holders would really know how big our business is they'd surely try to do something against it. They have no idea we are making millions in profit every month," it is alleged van der Kolk said during one.
But Dotcom's defence lawyer Ron Mansfield accused the Crown of "cherry picking" evidence, much of which was out of context and breached the duty of candour, he said.
Mr Mansfield said Megaupload was an internet service provider and as such was covered by safe harbour provisions in the Copyright Act.
That was not a defence to the allegations but a complete bar from prosecution, he said.
The defence argued "Mr Dotcom's dream idea" was created in response to large attachments being unable to be sent via email and was "copyright neutral".
"What the US is effectively saying to internet service providers is: 'you need to actively investigate copyright infringement and stop it, because if you don't you'll not only be civilly liable but criminally liable'," Mr Mansfield said.
Judge Dawson today said he would give an abridged version of his decision in open court before releasing his written judgement.
He did not indicate when that would likely take place.
