But the New York attorney general's office slammed the FCC's response as a deflection.

An FCC spokesperson, in a statement to CNBC, said Schneiderman's "so-called investigation is nothing more than a transparent attempt by a partisan supporter of the Obama Administration's heavy-handed internet regulations to gain publicity for himself."

The New York attorney general criticized the FCC for refusing to assist his office with the investigation.

Schneiderman, in an open letter , said an enormous number of fake comments were sent to the FCC about its move to repeal net neutrality rules. Those behind the scheme may have impersonated hundreds of thousands of real Americans by appropriating their names and addresses to make submissions, he said, in a scam akin to identity theft on a "massive scale."

New York Attorney General Eric Schneiderman and the Federal Communications Commission traded barbs on Wednesday over an investigation into a suspected scheme to manipulate the process through which Americans can weigh in on the FCC's move to repeal net neutrality rules.

"The potential impersonation of hundreds of thousands of Americans in order to influence the policy-making process should concern everyone — especially the FCC," said press secretary Amy Spitalnick.

"Yet rather than cooperate with our investigation, the commission has stonewalled it, and now offers political attacks to distract from the core issue — the manipulation of the FCC's own regulatory process," she said.

In his open letter Tuesday, Schneiderman said: "It is important that the public comment process actually enable the voices of the millions of individuals and businesses who will be affected to be heard."

But he said the FCC has essentially stonewalled his office by failing to provide evidence that is "crucial" to the investigation.

"The FCC has refused multiple requests for crucial evidence in its sole possession that is vital to permit that law enforcement investigation to proceed," Schneiderman said.

In a series of tweets on Tuesday, Schneiderman said his team has "received no substantive response" after reaching out to the FCC through a number of representatives.

@AGSchneiderman Over the last 6 mos, my office has investigated a massive scheme to corrupt the @FCC's comment process on #NetNeutrality by impersonating 100,000s of real Americans. The FCC has been unwilling to provide information that is critical to the investigation:

@AGSchneiderman We reached out for assistance to multiple top FCC officials, including @AjitPaiFCC, three successive acting FCC General Counsels, and the FCC's Inspector General. Yet we have received no substantive response to our investigative requests.

Schneiderman's letter did not specify if the comments in question predominantly sought to shift the voice of the public for or against the repeal of net neutrality rules.

The state attorney general expressed his own view on net neutrality in the letter, writing, "I have long publicly advocated for strong net neutrality rules ... and studies show that the overwhelming majority of Americans who took the time to write public comments to the FCC about the issue feel the same way while a very small minority favor repeal."

But Schneiderman said the suspected scheme should concern all Americans, irrespective of their political or personal views surrounding net neutrality, on grounds that a failure to pursue illegal activity will embolden its actors in the future.

He also appeared to reference the 2016 election of President Donald Trump. Multiple U.S. intelligence agencies have said Russia interfered in the election to favor Trump.

"In an era where foreign governments have indisputably tried to use the internet and social media to influence our elections," Schneiderman said, "federal and state governments should be working together to ensure that malevolent actors cannot subvert our administrative agencies' decision-making processes."