A former Oklahoma City police officer has been indicted on charges of training people to lie about crimes during polygraph tests as part of the Obama administration’s unprecedented crackdown on security violators and leakers.

Douglas Williams, 69, is accused of committing mail fraud and obstructing justice in a five-count indictment handed down Thursday in the Western District of Oklahoma. The indictment alleges that Williams, who runs the website Polygraph.com, trained two undercover agents to lie or conceal crimes during government lie-detector tests.

“Williams, who was paid for both training sessions, is alleged to have instructed the individuals to deny having received his polygraph training,” the Justice Department said in a news release sent out Friday.

By attempting to prosecute the instructor, federal officials are adopting a controversial legal stance that sharing such information should be treated as a crime and isn’t protected under the First Amendment in some circumstances. Williams has said he did nothing wrong.

“This is simply an attack on my First Amendment rights to free speech,” said Williams, who was notified of the indictment by a reporter. “This investigation is a way to go after me because I have the audacity to protest the use of the polygraph.”

McClatchy reported last year that one of the federal officials involved in the investigation had said in a speech that he thought that those who “protest the loudest and the longest” against polygraph testing “are the ones that I believe we need to focus our attention on.”

The federal government previously had treated such instructors only as nuisances, partly because the polygraph-beating techniques are unproven. Instructors have openly advertised and discussed their techniques online, in books and on national television. As many as 30 people or businesses across the country claim in Web advertisements that they can teach someone how to beat a polygraph test, according to U.S. government estimates.

John Schwartz, a U.S. Customs and Border Protection official, said in a speech that the effort to criminalize the teaching was part of the Obama administration’s Insider Threat Program, which is intended to deter what the government condemns as betrayals by “trusted insiders” such as Edward Snowden, the former National Security Agency contractor who revealed the agency’s secret communications data-collection programs.

The administration launched the Insider Threat Program in 2011 after Army Pfc. Bradley Manning, who now goes by Chelsea Manning, downloaded hundreds of thousands of documents from a classified computer network and sent them to WikiLeaks, the anti-government secrecy group.

“Nothing like this has been done before,” Schwartz said of the legal approach in the speech. “Most certainly our nation’s security will be enhanced.”

Schwartz acknowledged that teaching the techniques, known in polygraph circles as “countermeasures,” isn’t always illegal and might be protected under the First Amendment in some situations.

But instructors may be prosecuted if they know that the people they’re teaching plan to lie about crimes during federal polygraphs, he said.

Last year, an Indiana Little League coach pleaded guilty to similar charges and received eight months in prison.

Prosecutors described Chad Dixon as a “master of deceit” who taught as many as 100 people – including child molesters, intelligence employees and law enforcement applicants – how to beat lie detectors.

However, the federal judge who handed down the sentence against Dixon acknowledged “gray areas” between the constitutional right to discuss the techniques and the crime of teaching someone to lie while undergoing a government polygraph.

“There’s nothing unlawful about maybe 95 percent of the business he conducted,” the judge said of Dixon.

Williams might choose to fight the allegations given that he’s been a vocal opponent of the government’s use of polygraph tests.

Williams, a former police detective and polygrapher, has openly advertised his teachings for three decades, discussing them in detail on “60 Minutes” and other national news programs. A self-professed “crusader” who’s railed against the use of polygraph testing, he testified in congressional hearings that led to the 1988 banning of polygraph testing by most private employers.

The federal government, however, polygraphs about 70,000 people a year for security clearances and jobs. At the same time, most courts won’t allow polygraph results to be submitted as evidence against criminal suspects, citing the machines’ unreliability. Scientists question whether polygraphers can identify liars by interpreting measurements of blood pressure, sweat activity and respiration. Researchers say the polygraph-beating techniques can’t be detected with certainty, either.

Yet investigators confiscated business records from the two men, which included the names of as many as 5,000 people who’d sought polygraph-beating advice, McClatchy reported last year. U.S. agencies determined that at least 20 of them had applied for government and federal contracting jobs and at least half of that group was hired, including by the NSA. It’s unclear how many had been taught by Williams and whether any were caught lying.