Ken Kurson, a close friend of President Trump’s son-in-law Jared Kushner, was taken into federal custody on Friday and charged with cyberstalking in connection with his divorce.
Mr. Kurson, who now runs a media company and works in the cryptocurrency industry, helped write a speech for the president’s 2016 campaign. When Mr. Kushner owned The New York Observer, the weekly newspaper, he appointed Mr. Kurson to be its editor in chief in 2013.
Mr. Kurson was also a longtime associate of Rudolph W. Giuliani, Mr. Trump’s personal lawyer and the former New York City mayor.
Federal prosecutors in Brooklyn accused Mr. Kurson of sending threatening and stalking messages to several people, including a friend whom he blamed for the deterioration of his marriage.
The F.B.I. has also gathered evidence that Mr. Kurson engaged in a similar pattern of harassment during his divorce proceedings in 2015, including installing software on someone’s computer to monitor keystrokes, the criminal complaint said. He also used aliases to contact that person’s employer to report false allegations of misconduct, according to the complaint.
Mr. Kurson’s lawyer, Marc L. Mukasey, said in a statement: “Ken Kurson is an honorable man, a loving dad and a gifted writer. The conduct alleged is hardly worthy of a federal criminal prosecution. Ken will get past it.”
The criminal investigation began after the Trump administration offered Mr. Kurson a seat in 2018 on the board of the National Endowment for the Humanities, a federal body that distributes grants to museums, libraries and other cultural institutions.
As part of the routine background check for the position, the F.B.I. uncovered allegations of harassment against Mr. Kurson. He withdrew from consideration for the post shortly afterward, The New York Times reported in 2018.
Mr. Kurson resigned as editor of The Observer in 2017. During his four years there, the newspaper endorsed Mr. Trump for president as Mr. Kurson advised his campaign. While editing the newspaper, Mr. Kurson sat in the Trump family box at the Republican National Convention.
Mr. Kurson also helped run Mr. Giuliani’s presidential campaign in 2008 and wrote a book with him about leadership.
In 2018, Mr. Kurson created a website called Modern Consensus, which focuses on cryptocurrency and blockchain news. After leaving The Observer, he also joined the board of directors of Ripple, a cryptocurrency company.
A representative for Ripple did not immediately respond to a request for comment.