A New Zealand judge ruled on Wednesday that colorful Internet entrepreneur Kim Dotcom and three of his colleagues can be extradited to the United States to face criminal copyright charges.

Dotcom's lawyers said they have filed an appeal against the decision.

Judge Nevin Dawson's ruling came nearly four years after US authorities shut down Dotcom's file-sharing website Megaupload, which was once one of the Internet's most popular sites. Prosecutors say it raked in at least $175 million, mainly from people using it to illegally download songs, television shows and movies.

The US has charged the men with conspiracy to commit copyright infringement, racketeering and money laundering. If found guilty, they could face decades in jail.

But appeals to the extradition ruling are likely to take at least another year.

"It will end up in the Supreme Court, there's no doubt about it," said Dotcom's lawyer Ron Mansfield, referring to New Zealand's highest court. "The legal issues are so interesting and complex."

Judge Dawson, who presided over the nine-week hearing, wrote that "The overwhelming preponderance of evidence ... establishes a prima facie case to answer for all respondents on each of the counts."

The judge was required only to decide whether the U.S. had a valid case and not whether he thought the men were guilty or innocent.

The US argued the site cost copyright holders, which included Hollywood's major movie studios, more than $500 million. Prosecutors say intercepted communications show the men talking about being "modern-day pirates" and "evil."

Dotcom argued that he can't be held responsible for others who chose to use his site for illegal purposes and that any case should have been heard in civil court.

The case could have broader implications for Internet copyright rules. Mansfield said that if the US side prevails, websites from YouTube to Facebook would need to more carefully police their content.