Embattled Republican Congressman George Santos is facing an accusation of sexual misconduct from a former aide.
Derek Myers, 30, also accused Mr Santos of an ethics violation for having him work as a volunteer.
A job offer to Mr Myers was later rescinded, and Mr Santos told news outlet Semafor he was concerned by wiretapping charges faced by the aide during previous work as a journalist.
The accusations are the latest in a series of controversies for Mr Santos.
The BBC has reached out to the congressman's office for comment.
On Twitter on Friday, Mr Myers said he had filed a complaint to the Capitol police and wrote a letter to the House ethics committee, which can investigate violations of House rules, related to incidents he claims took place during his brief time working in Mr Santos's office.
The letter, which he posted online, details his allegations against Mr Santos. He said he was offered a job late last month in the Long Island congressman's office as his staff assistant.
The 34-year-old has faced growing calls to resign after he admitted fabricating parts of his resume and biography since his election in New York last year.
He is also facing multiple investigations over his campaign spending and financial reports. He has previously denied wrongdoing.
According to Mr Myers, on 25 January, Mr Santos asked him if he had a profile on Grindr, a popular LGBT dating app. Mr Santos then allegedly informed him that he had a profile on Grindr, Mr Myers said.
On a separate occasion the same day, Mr Myers was alone with Mr Santos in the congressman's office sorting mail.
"He called me 'buddy' and insisted I sit next to him on the sofa," Mr Myers wrote. "I proceeded to move forward with a discussion about the mail, but the congressman stopped me by placing his hand on my left leg, near my knee."
Mr Myers claimed the congressman then invited him to karaoke, which he declined, and proceeded to "take his hand and move it down my leg into my inner-thigh", where he "touched" his groin.
Next, Mr Myers said Mr Santos told him that his husband was away for the night and invited him to come over.
"I quickly pushed the congressman's hand away and grabbed the mail from the table and proceeded to discuss the topic of constituent correspondence," Mr Myers wrote.
Mr Myers was working under the status of "volunteer" at the time of the incident, he said, something he told was necessary as he waited for his new-hire paperwork to process through the payroll department. This was something he said he later learned was against House rules.
On Monday, 30 January, Mr Myers said he was called into Mr Santos' office and asked about his background as a journalist, matters that Mr Myers said had already been discussed prior to receiving a job offer.
Last year, he was charged with wiretapping while working as a journalist in Ohio after publishing audio of court testimony submitted by a courthouse source. The charges have been condemned by the Committee to Protect Journalists.
According to CBS, the BBC's US partner, Mr Myers said he pleaded not guilty to the charges and the case was automatically dismissed under Ohio's criminal rules of procedure after no indictment was brought within 60 days.
Mr Myers said his job offer in Mr Santos's office was rescinded on 1 February.
Last week, Mr Santos told Semafor he expected a progressive news website to publish recordings between the two men, saying: "He's violated the trust that we had in him". On Friday, Talking Points Memo published parts of a conversation the two had.
Mr Myers said he has not received any response to the letter from the House Ethics Committee, and that the Capitol Police told him a report would be ready on Monday, CBS reported.
"These matters will hopefully be appropriately addressed by the police and the Ethics Committee, respectively in due time," Mr Myers said.
