The New York Attorney General’s Office subpoenaed over a dozen different telecommunications lobbying groups on Tuesday to help determine whether they were behind an estimated 9.5 million fraudulent comments posted in support of the rollback of net neutrality, according to a report from The New York Times.

The investigation was launched last November, only a month before the Federal Communications Commission was set to vote on a proceeding that would roll back the open internet regulations instated under the Obama administration. Millions of comments were filed prior to that vote, and according to the attorney general’s office, 9.5 million of those may have been fraudulent.

“My office will get to the bottom of what happened and hold accountable those responsible.”

“The FCC’s public comment process was corrupted by millions of fake comments — and our investigation found that as many as 9.53 million of those comments stole the identities of real people,” AG Barbara Underwood said in a statement. “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.”

According to the attorney general’s office, the comments described were filed under false identities that were created through the use of temporary or even duplicated email addresses. Some comments appeared to be scripted and were repeated verbatim in millions of instances. According to a researcher at Stanford, an overwhelming majority of authentic comments were in support of net neutrality.

The Times reported that the subpoenaed organizations were telecommunications trade companies, all of which had a great stake in the outcome of the proceeding last year. These fraudulent comments were allegedly posted in support of the Pai commission’s ruling in an attempt to influence the FCC’s decision.

When launching the initial investigation, the NY AG’s office published an open letter to the FCC, critiquing the agency for acting uncooperatively and rejecting multiple requests for data related to the comment filing system.

The FCC declined to comment in an email to The Verge.