A New Zealand court is looking into the paramilitary raid on filesharing kingpin Kim Dotcom's mansion in January, having already found that the warrant justifying it was illegal.

Dotcom's mansion was raided at dawn by helicopter, which dropped off four heavily armed agents to launch the assault. They were followed by even more agents and dog handlers. The raid on the founder of Megaupload was coordinated, the government admits, with help from the FBI.

Dotcom and fellow executives face criminal copyright charges in the U.S.

Oddly, though the agents carried semi-automatic assault rifles, agents didn't wear full-body armor, as they weren't actually afraid of Dotcom fighting back.

You can find more details in the above video from New Zealand 3News' excellent, in-depth report.

Agents said the concern was that Dotcom would delete evidence, though as Dotcom pointed out in court, speaking directly to the government, there was little chance of that.

"You knew the FBI was in the data center, prior to you arriving," he said. "There was no chance for anyone to do anything with that evidence."

Dotcom explained that when the raid began, he didn't really understand what was happening, since early-morning helicopter landings aren't unusual at his pad and, speaking like a gamer, he explained that couldn't see out his windows.

"My shields were down so I couldn't see what was happening," Dotcom said. "Shortly afterward I heard banging on my door."

Dotcom said he sounded the alarm and retreated to a safe room, where he waited, seated, with the door unlocked and his hands empty, for the police to arrive. He contends that when the police did get to him, they used excessive force, including punching him in the face and stepping on his hand.

Dotcom is free on bail and is fighting extradition to the U.S., though hearings aren't scheduled until 2013.

The U.S. accuses Megaupload of making more than $500 million by encouraging and facilitating unlawful sharing of copyrighted movies and music. He and fellow executives say the allegations are a Hollywood witch-hunt. They face possible sentences of decades in prison if convicted.