Kim Dotcom has gone to the New Zealand High Court in a final bid to have the police raid on his Auckland mansion declared illegal.
The court case started early this week and is expected to slast for a couple of days.
Last February the Court of Appeal ruled that search warrants used in the 2012 raid on his house were lawful.
The police search warrants were used to seize vast amounts of material held on computers.
Some of that material may be used as evidence when the United States charge him for copyright breaches and money-laundering.