New York law enforcement officials this week issued subpoenas to more than a dozen pro-telecom industry groups as part of an investigation into millions of allegedly fraudulent public comments submitted to the Federal Communications Commission’s (FCC) website last year as the agency was preparing to repeal net neutrality protections.

“With the fog of fraud and spam lifted from the comment corpus, lawmakers and their staff, journalists, interested citizens, and policymakers can…better understand what Americans actually said about the repeal of net neutrality protection.” —Ryan Singel, Stanford University

A vast majority of the 22 million comments are thought to have been fake, according to the office of New York Attorney General Barbara Underwood, who issued the subpoenas.

“The FCC’s public comment process was corrupted by millions of fake comments,” Ms. Underwood said in a statement Tuesday. “The law protects New Yorkers from deception and the misuse of their identities. My office will get to the bottom of what happened and hold accountable those responsible for using stolen identities to distort public opinion on net neutrality.”

The groups accused of orchestrating a deluge of anti-net neutrality comments include Broadband for America, Century Strategies, and “conservative messaging firm” Media Bridge—which openly wrote in a press release that one of its clients had submitted nearly 800,000 comments to the FCC’s website.

Open internet defenders Free Press and Fight for the Future have also been subpoenaed, according to the Wall Street Journal—but both support the attorney general’s probe.

“We are responding to their requests and welcome this inquiry,” Free Press spokesman Tim Karr told the Journal.