Rob Porter, left, White House Staff Secretary speaks to President Donald Trump after Trump made remarks regarding the on going situation in Charlottesville, Va., Saturday, Aug. 12, 2017 at Trump National Golf Club in Bedminister, N.J.

The House Judiciary Committee on Monday issued a subpoena to Rob Porter, a former White House aide who worked closely with President Donald Trump, as part of the panel's investigation into alleged corruption by Trump and his associates.

Porter, 41, was subpoenaed to testify before the committee on Sept. 17 by Judiciary Chairman Jerry Nadler, D-N.Y. Porter is being asked to testify on the same day as two other Trump associates — ex-Trump campaign manager Corey Lewandowski and former White House deputy chief of staff Rick Dearborn — who were subpoenaed earlier this month.

Nadler said the testimony from Porter and others will "help the committee determine whether to recommend articles of impeachment against the president or other Article 1 remedies."

"No one is above the law," Nadler said in a statement.

All three men are mentioned in former special counsel Robert Mueller's report on Russian election interference, possible coordination between Trump's campaign and the Kremlin, and possible obstruction of justice by Trump himself.

"These witnesses were all involved in President Trump's extensive efforts to obstruct the special counsel's investigation," representatives for the committee's Democratic majority said in a press release.

Porter, who was reportedly interviewed by Mueller's team for a total of about 20 hours, is among the most-cited sources in Mueller's 448-page report.

After The New York Times reported in January 2018 that Trump had unsuccessfully tried to have Mueller fired, the president allegedly directed Porter to tell the White House counsel, Don McGahn, to write a letter denying the article.

McGahn "shrugged off the request," according to the Mueller report, "explaining that the media reports were true."

"McGahn told Porter that the president had been insistent on firing the special counsel and that McGahn had planned to resign rather than carry out the order," the Mueller report says.

Porter served as Trump's staff secretary until his abrupt resignation in February 2018, after two of his ex-wives accused him of physically and verbally abusing them during their marriages. One of his ex-wives spoke out in U.K. tabloid The Daily Mail, claiming that Porter choked and punched her during their five-year marriage.

Porter denied the claims. "These outrageous allegations are simply false," he said at the time. I took the photos given to the media nearly 15 years ago and the reality behind them is nowhere close to what is being described. I have been transparent and truthful about these vile claims, but I will not further engage publicly with a coordinated smear campaign."

The White House declined to comment on Porter's subpoena.

In a statement Monday, Nadler said Porter was "prominently featured in the special counsel's description of President Trump's efforts to obstruct justice by directing then-White House Counsel Don McGahn to fire the Special Counsel, and then ordering him to lie about it."

Like Porter, Lewandowski is mentioned dozens of times in Mueller's report.

The report says that Trump, in June 2017, told Lewandowski in an Oval Office meeting to give then-Attorney General Jeff Sessions a message directing Sessions to call Mueller's probe "very unfair."

Lewandowski said he understood the request but then asked Dearborn to deliver it for him, according to the Mueller report. Dearborn did not deliver the message.

Lewandowski is now publicly hinting that he is considering a Senate run in New Hampshire.