WELLINGTON, New Zealand -- Flamboyant internet entrepreneur Kim Dotcom and three of his former colleagues have lost their latest bid to avoid extradition to the U.S. to face criminal charges. New Zealand's Court of Appeal on Thursday upheld earlier court rulings that found the men were eligible to be handed over to U.S. authorities.

Dotcom's lawyer Ira Rothken said they were disappointed with the judgment and planned to file an appeal with New Zealand's Supreme Court.

"We have now been to three courts each with a different legal analysis," Rothken wrote on Twitter.

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The latest decision comes more than six years after U.S. authorities shut down Dotcom's file-sharing website Megaupload and filed charges of conspiracy, racketeering and money laundering against the men. If found guilty, they could face decades in prison.

Megaupload was once one of the internet's most popular sites. U.S. prosecutors say it raked in at least $175 million, mainly from people using it to illegally download songs, television shows and movies.

Dotcom argues that he can't be held responsible for others who chose to use his site for illegal purposes, and that any case against him should have been heard in civil court. He says he never lived in the U.S. or even visited the country and didn't have a company there.

Born in Germany as Kim Schmitz, Dotcom founded Megaupload in 2005. At one point he lived in a Hong Kong hotel, before being granted permanent residency in New Zealand in 2010. He was arrested in New Zealand in 2012 during a dramatic police raid on his mansion and incarcerated for a month before being released on bail.

Since then, Dotcom has released a music album, started another internet file-sharing company called Mega and launched a political party, which unsuccessfully contested the nation's 2014 election.

In addition to Dotcom, who founded Megaupload and was its biggest shareholder, the U.S. is also seeking to extradite former Megaupload officers Mathias Ortmann, Bram van der Kolk and Finn Batato.