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The House Ethics Committee on Thursday kicked off a formal investigation into two Republican congressmen who were charged last month in separate federal indictments.

The House established two “investigative subcommittees” to look into the conduct of Reps. Duncan Hunter, R-Calif., and Chris Collins, R-N.Y. The creation of such panels is the equivalent of a congressional indictment and is seen as a signal that the House views the lawmakers' conduct as potentially problematic and worthy of inquiry.

Hunter and his wife, Margaret, stand accused of spending more than $250,000 in campaign funds on lavish personal expenses including trips, theater tickets, tequila shots and groceries. They allegedly attempted to conceal the spending by passing it off in federal records as a legitimate use of donations to "wounded warriors" and other charities or money from other fundraising events.

The couple pleaded not guilty during an appearance in federal court in San Diego earlier this week. No date was set for the trial, but it could begin in late November or later.

Collins – along with his son, Cameron, and Stephen Zarsky, the father of his son’s fiancée – were indicted on insider trading charges in connection with an Australian pharmaceutical company.

Prosecutors allege that Collins passed along secrets to his son, Cameron, in June 2017. They say the son traded on the inside information and passed it to Zarsky. They added that Zarsky traded on it and tipped off at least three others.

Among the charges, the defendants are accused of multiple counts of securities fraud, along with one count of wire fraud, one count of conspiracy to commit wire fraud and one count each of making false statements.

All three pleaded not guilty in a Manhattan court in early August.

At the time of their indictments, both Hunter and Collins faced re-election challenges. Hunter has not exited his race, while Collins suspended his run days after his indictment. Both seats appear likely to remain in GOP hands, but the charges have raised Democratic hopes.

President Trump faced bipartisan criticism after tweeting Monday that the Justice Department's indictments against Hunter and Collins had put the GOP in jeopardy in the midterm elections.

"It was over and above what he's done before," Sen. Jeff Flake, R-Ariz., told reporters. "To say the Justice Department ought to punish his enemies and protect his friends goes beyond what any president in my memory has ever said, and that we can't normalize that."

Trump's tweet also drew a scolding on Monday by Sen. Ben Sasse, a Nebraska Republican who sits on the Judiciary Committee.

"The United States is not some banana republic with a two-tiered system of justice — one for the majority party and one for the minority party," Sasse said in a statement.

Fox News’ Chad Pergram and The Associated Press contributed to this report.