Rep. Chris Collins, R-N.Y., resigned suddenly from Congress ahead of his expected guilty plea in an insider trading case.

Collins sent a letter of resignation that officially took effect when Congress met in a brief session on Tuesday.

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It would be up to Gov. Andrew Cuomo to set a special election to fill the seat, which leans Republican. Collins has served as the representative of New York’s 27th District since 2013.

Collins was among the first members of Congress to endorse President Donald Trump’s presidential campaign.

Court records say he is expected to plead guilty in a criminal case accusing him of insider trading.

A federal judge in Manhattan has scheduled a hearing Tuesday afternoon for U.S. Rep. Chris Collins to enter a guilty plea in a case initially brought last year.

“The fraud counts against Collins relate to securities of an Australian biotechnology company called Innate Immunotherapeutics; the 69-year-old congressman served on the board,” Fox News reported on Tuesday.

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“According to the original indictment, Collins specifically got early word that a drug the company had developed for the treatment of multiple sclerosis wasn’t performing well in a medical trial and passed the tip to his son. Prosecutors said the three avoided more than $768,000 in losses by trading ahead of the public announcement of the failed drug trials,” Fox wrote.

A similar hearing has been scheduled Wednesday for Collins’ son.

Collins’ attorney didn’t immediately respond to messages Monday. The U.S. attorney’s office in Manhattan also declined to comment.

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The Associated Press contributed to this article