A man accused of writing racially hateful letters to prominent blacks, including U.S. Supreme Court Justice Clarence Thomas, is expected to plead guilty in federal court, attorneys said Wednesday.

David Tuason, 46, of the Cleveland suburb of Pepper Pike, is accused of writing threatening letters over two decades, often targeting black men seen with white women.

Acting U.S. Attorney Bill Edwards and Donna Grill, an assistant public defender, said they expect him to enter a plea Thursday admitting to charges of transmitting threatening interstate communications and mailing threatening communications.

He pleaded not guilty last month but will change that under a plea agreement, details of which were not released.

Authorities say FBI agents found Tuason a few months ago when he started sending messages via e-mail instead of U.S. mail. The letters dated to the late 1980s and appeared to stop in the early 1990s, only to start again later that decade.

Letters and e-mails described in the charges contain threats of violence based on racial hatred. New York Yankees shortstop Derek Jeter, Miami Dolphins defensive lineman Jason Taylor and actor Taye Diggs were among those believed to have been targets.

According to the April 9 indictment, Tuason sent a letter to the Supreme Court on July 25, 2003, addressed to an associate justice of the court referred to as "CT." The indictment used only the initials of victims.

In the letter, which contained several racially derogatory remarks, the writer threatened to blow up the Supreme Court building, and wrote that "CT" would be "castrated, shot or set on fire. ... I want him killed."