A Republican senator from Kentucky has joined calls for an investigation into the National Security Agency (NSA) alleged monitoring of Tucker Carlson.

Sen. Rand Paul sent an open letter to the NSA Director Gen. Paul Nakasone to request an investigation into the agency’s alleged spying and unmasking of the Fox News host.

“Carlson is a journalist, who currently hosts the popular news program ‘Tucker Carlson Tonight,’ and as such he is to be afforded the freedom of the press protections guaranteed by the First Amendment to the U.S. Constitution,” Paul said in the letter. “Carlson recently alleged on his television show that the NSA … read his private emails relating to his attempt to interview Russian President Vladimir Putin.”

Paul also demanded to know exactly how NSA leaked the host’s private emails to different mainstream media companies.

“NSA [also allegedly] unmasked his identity and leaked his private emails, which identified him by name to others in the press,” he said.

The senator invited NSA to prove it did not monitor or leak Carlson’s electronic communication.

“I am open-minded enough to believe, if given convincing evidence, that the NSA may be telling the truth,” he said.

However, he is dissatisfied with the agency’s Twitter post that denies Carlson was ever an “intelligence target” and claims to have no plans to “try to take his program off the air.”

“When a long train of abuses conducted by the NSA evinces a consistent design to evade the law and violate the constitutionally-protected liberties of the people, the NSA must do more than tweet a carefully worded denial to be trusted,” he said.

Paul hopes Gen. Nakasone will help restore the NSA’s credibility through showing a real commitment to transparency.

“[Start] by being completely honest with the American people and explaining in detail whether the NSA conducted surveillance on Tucker Carlson in his role as a journalist, … whether you or anyone else within the federal government approved his alleged unmasking, and whether Mr. Carlson’s private emails were shared with any other reporters or news organizations,” he said.

The senator also sent the director four questions and compelled him to answer.

The first asks whether Carson has ever been an NSA target, or whether the agency incidentally collected his electronic communications relating to his attempts to interview Russian President Vladimir Putin.

“Has the NSA, for any reason and in any manner, obtained Carlson’s electronic communications relating to his attempt to interview Vladimir Putin,” he said.

The Republican also wants to know if the NSA complied with federal law, requiring the use of minimization procedures during surveillance to protect American identities.

“If Carlson was indeed unmasked, what was the lawful justification for his unmasking?” he said.

Finally, he also wants to know if Gen. Nakasone personally investigated whether Carlson’s allegations are true.

“Was [there] a leak of Mr. Carlson’s emails to other reporters or news organizations?” he said. “Relatedly, are you committed to bringing the leaker or leakers to justice?”

The questions came after House Republican Leader Kevin McCarthy (R-Calif.) announced House Intelligence Committee ranking member Devin Nunes (R-Calif.) would investigate the NSA following Carlson’s allegations.

“NSA cannot be used as a political instrument, and House Republicans will ensure accountability and transparency,” McCarthy said in a statement.

Carlson revealed in June that a federal government insider called him to warn the NSA had intercepted his emails and text messages in a bid to remove his show.

“We heard from a whistleblower within the U.S. government who reached out to warn us that the NSA, the national security agency, is monitoring our electronic communications and is planning to leak them in an attempt to take this show off the air,” he said.

“Now that is a shocking claim and, ordinarily, we would be skeptical. It is illegal for the NSA to spy on American citizens, it is a crime,” he added.