Two senators say their identities were among the millions of fraudulent comments that were allegedly posted to Federal Communications Commission‘s (FCC) website ahead of its controversial vote to repeal net neutrality rules last year. The senators are questioning the agency about its investigation into instances of identity fraud.

Sen. Jeff Merkley (D-Ore.) and Sen. Pat Toomey (R-Pa.) sent a letter Monday to FCC Chairman Ajit Pai asking the agency to “identify and address fraudulent behavior in the rulemaking process.” The two lawmakers said both of their identities were used to make false statements ahead of the vote.

The calls from Merkley and Toomey come as a torrent of criticism has been levied against the FCC for fraudulent comments that were among more than 20 million left on its website before its vote to dismantle net neutrality rules last year.

“We need to prevent the deliberate misuse of Americans’ personal information and ensure that the FCC is working to protect against current and future vulnerabilities in its system,” the letter reads.

The fake comments left on the FCC’s website were also the subject of an investigation in New York. Fraudulent comments were left by people claiming to live in Florida, Texas, and California in addition to New York. The fake comments were also brought up by FCC Commissioner Jessica Rosenworcel before the agency’s vote on net neutrality last year.

Merkley and Toomey suggest in the letter that the FCC consider using CAPTCHA technology to differentiate between humans leaving comments and fake ones. The two senators also asked Pai to answer several questions including:

How is the FCC working with the Department of Justice to identify those who submitted fake comments?

Is the FCC working with state attorneys general to determine whether state crimes were broken when these identities were stolen?

How can the FCC track down who misused the identities of 2 million Americans?

Is the FCC aware of any foreign government submitting fake comments, and if yes, for what purpose?

“These Senators are asking exactly the right questions,” Evan Greer, the deputy director of digital advocacy group Fight for the Future, said in a statement. “Providing oversight for the FCC is Congress’ job.”

Last week, the Senate voted by a 52 to 47 margin to begin a process using the Congressional Review Act (CRA) that could undo the FCC’s net neutrality decision. The House of Representatives will now vote on the net neutrality CRA. If successful in the House, President Donald Trump would ultimately need to sign it to undo the agency’s decision.

Last year, lawmakers in both the Senate and the House asked for investigations into the fake net neutrality comments.

In response to the Senate’s request, the FCC said lawmakers are being “desperate” in an attempt to delay the net neutrality vote.

You can read all of Merkley and Toomey’s letter here.