A Connecticut man has been arrested on charges that he threatened to kill Representative Adam Schiff of California, the Democrat who was the lead impeachment manager in the House during the proceedings against President Trump, federal prosecutors announced on Monday.

The man, Robert M. Phelps, 62, of Torrington, Conn., used a meeting request form on Mr. Schiff’s congressional website to send the expletive-laden threats, which were made on Nov. 12, the eve of the first public impeachment hearing, according to a criminal complaint.

Mr. Phelps was taken into custody on Friday and made a brief appearance the same day in U.S. District Court in Connecticut. He was at least the third person to be charged with threatening Mr. Schiff, a former federal prosecutor who became the face of the impeachment case against Mr. Trump. Several other Democratic lawmakers have faced similar death threats.

Prosecutors said that Mr. Phelps wrote, “I want to come and see you so I can spit in your face and I want to kill you with my bare hands and smash your sick little round fat lying face in.”