Chris Collins, former U.S. Representative for New York's 27th congressional district, arrives at Federal Court in New York, October 1, 2019.

Former Republican Rep. Chris Collins pleaded guilty Tuesday to charges in an insider trading case lodged by federal prosecutors while he was a member of the House.

Collins pleaded guilty to charges of conspiracy to commit securities fraud and making false statements, multiple outlets reported.

Collins, 69, changed his plea in Manhattan federal court a day after submitting his resignation from Congress, where he had represented New York's 27th District since 2013. His resignation letter, sent to House Speaker Nancy Pelosi, D-Calif., was read on the House floor Tuesday morning.

"By virtue of his position, Collins helped write the laws of this country and acted as if the law didn't apply to him," Geoffrey Berman, U.S. attorney for the Southern District of New York, said outside the courthouse following Collins' guilty plea.

"Collins is now a convicted felon and no longer a member of Congress," Berman said.

The New York Daily News reported that Collins said in court that he was "embarrassed and dismayed" by what he had done. "The actions I took are anything but what a model citizen would take," he reportedly said.

Collins did not stop to answer reporters' questions as he left the lower Manhattan courthouse.

Collins was arrested in August 2018 on charges of insider trading and lying to an FBI agent. Federal prosecutors accused him of calling his son in a panic from the White House lawn to share information about a failed drug trial conducted by an Australian biotech company in which he was a major stakeholder.

His son, Cameron Collins, then allegedly sold thousands of shares of the company's stock before the drugmaker, Innate Immunotherapeutics, issued a press release about the failed trial. The company's stock plummeted more than 90% in the next trading session after the press release was sent out, according to the indictment. Collins saved more than $570,000 by trading on the tip from his father, prosecutors allege.

Cameron Collins and Stephen Zarsky, the father of his fiancee, were also charged in the indictment.

Chris Collins, who was reported to be one of the 10 richest members of Congress during his first term in 2012, pleaded not guilty to the charges on the day of his arrest.

He suspended his 2018 reelection campaign shortly thereafter — but revived it about a month later and won his race.

Collins was the first member of Congress to back President Donald Trump's 2016 campaign. Collins' district voted more solidly for Trump than any other district in New York.

Before his change-of-plea hearing was revealed, it had appeared as though Collins was gearing up for fights in politics and in the courts.

In mid-September, all three men once again pleaded not guilty to a slightly revised indictment, which cut references that could be argued are "protected by the Speech and Debate Clause" of the U.S. Constitution, according to a letter from federal prosecutors.

That plea came a few months after Collins reportedly dumped $500,000 of his own money into his campaign fund, which was seen as a signal that the Republican would be running for reelection.

Cameron Collins and Zarsky have their own change-of-plea hearings set for 2 p.m. on Thursday.