One of the attorneys behind the Prenda Law "copyright trolling" scheme has pleaded guilty to federal charges of fraud and money laundering.

After years of denial, John Steele admitted Monday that he and co-defendant Paul Hansmeier made more than $6 million by threatening Internet users with copyright lawsuits.

It's perfectly legal to sue Internet pirates—but not the way Steele did it. Steele and Hansmeier set up "sham entities" to get copyrights to pornographic movies, "some of which they filmed themselves," according to the Department of Justice's statement on the plea. Steele and Hansmeier then uploaded those movies to file-sharing websites such as The Pirate Bay and then sued the people who downloaded the content.

Steele and Hansmeier hid their role in making the porn and hid the fact that they had a personal stake in the outcome of the litigation. They subpoenaed Internet service providers to get subscriber information and then sent letters and made phone calls to the victims, threatening them with "enormous financial penalties and public embarrassment unless they agreed to pay a $3,000 settlement fee."

The guilty plea brings to a close a long and bizarre saga of profiting from copyright lawsuits, in which Steele came into conflict with his former housekeeper and even his own mother-in-law. It all began unwinding in the spring of 2013, when US District Judge Otis Wright sanctioned the duo for having "defrauded the court" and submitted their case to the FBI.

In 2013, the attorneys linked to Prenda Law began to file bizarre anti-hacking lawsuits in state courts. Defendants accused Prenda lawyers of recruiting "sham" defendants to get ISP subscriber information, and Steele has now admitted that's exactly what happened.

Steele will be sentenced by US District Judge Joan Ericksen of the District of Minnesota. The sentencing hasn't been scheduled yet.

His alleged co-conspirator, Paul Hansmeier, was also arrested and charged at the same time as Steele. Hansmeier's case hasn't yet been resolved. Hansmeier lost his law license last year after legal regulators accused him of the same types of activity that the FBI and IRS have investigated.