WASHINGTON — The House Ethics Committee said on Thursday that it was investigating allegations that a Democratic freshman, Delegate Michael F. Q. San Nicolas of Guam, had a sexual relationship with a congressional staff member, a violation of House rules, and broke campaign finance laws.
A former chief of staff and campaign official for the delegate accused Mr. San Nicolas in September of having an affair with a woman he then hired onto his congressional staff. The former staff member, John Paul Manuel, also alleged that Mr. San Nicolas used campaign funds to pay for a trip he took with the woman, according to The Guam Daily Post. Mr. Manuel also accused Mr. San Nicolas of accepting more than the $2,700 limit in campaign contributions from a single donor as a candidate.
“The congressman welcomes the opportunity for due process,” the delegate’s office said in a brief statement.
When Mr. Manuel filed a formal complaint with the Guam Election Commission in September, Mr. San Nicolas told The Pacific Daily News that the allegations were “baseless” and the timing of that filing was intended “to cause maximum political damage.”
Mr. San Nicolas, a freshman and the sole nonvoting delegate representing the United States territory, serves as vice chairman of the House Financial Services Committee.
It was the second time in two days that the Ethics Committee had announced an investigation into allegations that a House lawmaker had a sexual relationship with a congressional staff member. The investigations are the first public ones opened by the committee since the House codified language this year barring lawmakers from having relationships with staff members.
On Wednesday, the committee announced that it was looking into allegations that Representative Katie Hill of California, another Democratic freshman, had a sexual relationship with a member of her congressional staff.
In both instances, the committee noted that “the mere fact that it is investigating these allegations, and publicly disclosing its review, does not itself indicate that any violation has occurred, or reflect any judgment on behalf of the committee.”
Ms. Hill has acknowledged a separate relationship with a member of her campaign team, but denied the allegation the committee. is investigating The rules do not cover campaign staff members.
Lawyers for Ms. Hill sent a cease-and-desist letter on Thursday to The Daily Mail, after the website published nude photos said to be of Ms. Hill.
“By spreading these purported claims, and dehumanizing and shaming images across the globe, you have perpetuated the cycle of abuse Representative Hill has endured,” the two lawyers, Marc E. Elias and Rachel L. Jacobs, from Perkins Coie, wrote in the letter, which was obtained by The New York Times and first reported by HuffPost.
The two lawyers also said another claim by The Daily Mail that Ms. Hill “has Nazi imagery on her body in the form of a tattoo is false and defamatory.”
Sheryl Gay Stolberg contributed reporting. Kitty Bennett contributed research.