New York Attorney General Eric Schneiderman revealed today that his office has been investigating a flood of spam FCC comments that impersonated real people, and criticized the FCC for withholding useful information. In an open letter addressing FCC chairman Ajit Pai, Schneiderman writes that his office has spent six months investigating who submitted hundreds of thousands of identical anti-net neutrality comments under the names and addresses of unwitting Americans. But he says that the FCC has ignored multiple requests for logs and records, offering “no substantive response.”

Schneiderman argues that the fake comments constitute illegal impersonation and misuse of a person’s identity, and that “tens of thousands” of New York state residents are potentially affected. “The perpetrator or perpetrators attacked what is supposed to be an open public process by attempting to drown out and negate the views of the real people, businesses, and others who honestly commented on this important issue,” he writes. Using real names to do it is “akin to identity theft, and it happened on a massive scale.”

He says that his office first contacted the FCC in June, and has made at least nine requests between June and November, seeking confidential access to records related to the FCC’s comment system. “Yet we have received no substantive response to our investigative requests. None,” he says. Schneiderman didn’t specify how exactly these records might help the investigation, but he says they are “necessary” to figure out who was behind the comments.

Schneiderman’s statement was posted soon after the FCC announced plans to repeal net neutrality rules next month, weakening or possibly eliminating rules that stop ISPs from selectively slowing or blocking web traffic. He says this letter isn’t meant to be a political statement about these rules, but it implies that the FCC made its decision based on invalid information. “The process the FCC has employed to consider potentially sweeping alterations to current net neutrality rules has been corrupted by the fraudulent use of Americans’ identities  —  and the FCC has been unwilling to assist my office in our efforts to investigate this unlawful activity,” he writes.

People whose names were attached to fake comments have previously urged the FCC to run its own investigation into the comments, and Sen. Frank Pallone (D-NJ) requested an FBI probe in June. But the FCC has stayed generally quiet about the issue, and the agency didn’t immediately return an emailed request for comment about this latest news.

Public comments played a huge role in helping pass strong net neutrality rules in 2015, but this time around, the process was a mess. Many comments were made under assumed names or disposable email addresses, and the system briefly crashed in early May, when the FCC claimed it had been hit with a denial-of-service attack. The agency also said that it wasn’t basing its proposal on the quantity of submissions supporting or opposing net neutrality — which means it may well argue that the fake comments are a moot point.