Anthony D. Weiner, the former Democratic congressman whose sexting scandals ended his political career and embroiled him in a tumultuous F.B.I. investigation of Hillary Clinton before the election, is to appear in a federal courtroom in Manhattan on Friday to enter a guilty plea.
The information has not been made public but was related by two people who have been briefed on the matter and asked not to be identified.
Mr. Weiner will plead guilty to a single charge of transferring obscene material to a minor, pursuant to a plea agreement with the United States attorney’s office in Manhattan, one of the people said. Mr. Weiner surrendered to the F.B.I. early Friday morning.
The federal authorities have been investigating reports that, beginning in January 2016, Mr. Weiner, then 51, exchanged sexually explicit messages with a 15-year-old girl in North Carolina.
The plea covers conduct by Mr. Weiner from January through March of last year, the person said. A likely result of the plea is that Mr. Weiner would end up as a registered sex offender, although a final determination has yet to be made, the person added.
The charge carries a potential sentence of zero to 10 years in prison, meaning that Mr. Weiner could avoid prison. The ultimate sentence would be determined by a judge.
Reports of the federal investigation surfaced in September after a British newspaper, The Daily Mail, reported that Mr. Weiner had engaged in an online relationship with the girl, which included explicit messages sent over social media and suggestive texts.
It was during the investigation that the F.B.I. seized Mr. Weiner’s electronic devices, including a laptop on which agents found a trove of emails to his estranged wife, Huma Abedin, a top aide to Mrs. Clinton. That discovery led to the surprise announcement in late October by James B. Comey, then the F.B.I. director, that the bureau was conducting a new investigation into Mrs. Clinton’s handling of official email, an inquiry that ended two days before the election, with no charges brought.
Mrs. Clinton recently attributed her election loss in part to Mr. Comey’s announcement.
A defendant’s decision to plead guilty, of course, is subject to change at the last minute. A representative of the United States attorney’s office in Manhattan had no comment on the case.
The Daily Mail article said that Mr. Weiner began exchanging messages with the girl when she was a high school sophomore and that the messages indicated that Mr. Weiner knew that she was underage.
The newspaper, which did not identify the girl, said she did not want to press charges “because she believes her relationship with Weiner was consensual.” The paper said that she and her father agreed to be interviewed “out of concern that Weiner may be sexting with other underage girls.”
Mr. Weiner was forced to resign from Congress, where he represented parts of Queens and Brooklyn, in June 2011, not long after an explicit picture, sent from his Twitter account, became public. Mr. Weiner initially claimed that his account had been hacked but eventually admitted that he had lied and that he had sent the image and had inappropriate online exchanges with at least six other women.
An effort to resurrect his career progressed in 2013 as he began his candidacy for mayor of New York. But that, too, collapsed after the emergence of additional explicit online messages.
Mr. Weiner’s marriage to Ms. Abedin fell apart after new suggestive text messages surfaced in August, including one with an image of Mr. Weiner’s crotch as he lay next to the couple’s son, who was 4.