WASHINGTON (AP) — Jerome Corsi, a conservative author and conspiracy theorist who was a target in special counsel Robert Mueller's investigation, says the Justice Department is now scrutinizing his communications with a doctor who has touted an anti-malaria drug as a treatment for the new coronavirus.

The drug hydroxychloroquine has not been proven to help symptoms of COVID-19, and could cause deadly side effects, but the doctor has still promoted it publicly, as has President Donald Trump.

In a video posted on YouTube, Corsi said he mistakenly sent an email meant for Dr. Vladimir "Zev" Zelenko to federal prosecutor Aaron Zelinsky because they are similar names in his address book.

Zelinsky had worked on Mueller's team during the Russia investigation and was one of the prosecutors who had been investigating Corsi, an associate of former Trump campaign adviser Roger Stone. Mueller's investigators were trying to determine whether Corsi and Stone had advance knowledge of WikiLeaks' plans to release hacked material damaging to Hillary Clinton's 2016 presidential effort. He was never indicted. Stone was convicted on other charges brought as part of the investigation into whether the Trump campaign coordinated with Russia.

Corsi said in his video that he was working with Zelenko on a website to connect people with doctors who could prescribe the drug and then have the prescription filled and mailed express to the patients. He was responding to questions from The Washington Post, which first reported the investigation.

He described Zelenko as an unpaid medical adviser and said he had inadvertently copied Zelinsky, the prosecutor, on an email to business associates. In the email, he wrote that Zelenko had "FDA-approved randomized" testing of the drug, according to a copy of the message he displayed in his video.

The prosecutor responded to the email by asking Corsi if he had an attorney, and then told Corsi's lawyer that he had checked a government website of approved clinical trials and found no mention of Zelenko.

After that, Corsi said he reached out to the doctor to double check whether the study had been approved by the Food and Drug Administration and eventually learned it had not.

Corsi insisted he acted lawfully and that Zelenko had made a mistake. He said he would cooperate fully with investigators, and so far Zelinsky has asked him to turn over his communications with Zelenko, which he has done, he said.

It's unclear exactly what the Justice Department might be investigating. Zelinsky is one of dozens of prosecutors investigating coronavirus-related fraud cases. Justice officials declined to comment.

Critics have accused the doctor of getting ahead of scientific research during his on-air interviews with Fox News. It's not clear, either, if Trump, a religious Fox News watcher, is basing any of his belief in the drug on Zelenko's comments.

Trump has repeatedly touted the malaria drug during his frequent press briefings, calling it a "game changer" and suggesting skeptics would be proved wrong. He has offered patient testimonials that the drug is a lifesaver.

He pushed the drug as a possible salve even as Dr. Anthony Fauci, the government's top infectious disease expert, has cautioned that no definitive studies had been conducted to show it was effective and safe for treating coronavirus patients.

"It's been around for a long time, so we know if things don't go as planned it's not going to kill anybody," Trump said in March.

At one moment during the crisis, he noted "a lot of people are saying" patients should take the drug and called it "a very special thing." He's also repeatedly suggested that infected Americans who take it in consultation with their doctors have nothing to fear.

"What do you have to lose," said Trump, who has said that he's considered taking the drug preemptively to try to stave off the virus.

But even as Fauci gave caution, others close to the president, including White House trade adviser Peter Navarro, have made the case for the drug and have pushed back against Fauci.

In a heated Situation Room meeting of the White House's coronavirus task force last month, Navarro challenged him over his concerns about recommending the drug based only on unscientific anecdotal evidence.

Navarro, who has no formal medical training, erupted at Fauci, raising his voice and claiming the reports of studies he had collected were enough to recommend the drug widely, according to a person familiar with the exchange who spoke on the condition of anonymity to describe the blow-up.

The FDA last week warned doctors against prescribing hydroxychloroquine for treating the coronavirus outside of hospitals or research settings because of reports of serious side effects, including dangerous irregular heart rhythms and death among patients.

___

Associated Press writer Regina Garcia Cano contributed to this report.