An Ohio man has been indicted on charges that he threatened to blow up the U.S. Supreme Court building and attack an associate justice on the court, according to an indictment filed in federal court in Cleveland on Wednesday.

David Tuason, 46, of Pepper Pike, targeted black men known to affiliate with white women, white women who had relationships with black men, and children of mixed-race parents, federal authorities said. Approximately 200 threats, in letters and e-mails, were sent out over the course of 20 years, said acting U.S. Attorney William J. Edwards.

Supreme Court spokeswoman Kathy Arberg confirmed that Justice Clarence Thomas was threatened in the case but declined further comment.

According to the indictment, Tuason sent a letter to the Supreme Court building in July 2003 addressed to an associate justice of the court referred to as "CT."

In the letter, which contained several racially charged remarks, he threatened to blow up the building, and claimed "CT" would be "castrated, shot or set on fire ... I want him killed," says the indictment filed in the U.S. District Court for the Northern District of Ohio.

Thomas is the only black justice sitting on the Supreme Court.

A former Cleveland Cavaliers player and his family members were among others threatened, Edwards said.

According to the indictment, one of the letters referred to an "LN" and mentions the Cavaliers and was sent last year to Revere High School in Richfield, where the daughter of former Cavaliers star, Larry Nance, is a student and accomplished athlete.

Also targeted was a well-known black singer who performed at Cleveland's Severance Hall, home of the city's orchestra, about the time a February letter was sent, Edwards said.

The letter sent Feb. 4 addressed an "AJ," according to the indictment, and Grammy-award winning jazz and R&B artist Al Jarreau was on the venue's schedule on Feb. 8.

Edwards and FBI spokesman Scott Wilson declined to name those targeted, citing privacy issues.

Wilson said the threats began in Cleveland and branched out across the nation. He would not specify whether Tuason attempted to carry out attacks, but said he acted alone.

"As far as we know, it's a one-man operation," Wilson said.

The indictment says letters were also sent to several Ohio sites, including the Kent State University women's basketball team, several Ohio high schools and the Severance Hall home of the Cleveland Orchestra. The earliest letter was sent to a high school track team in Mentor in May 2003, according to the document. The most recent threat, to a high school football team in Strongsville, was mailed March 3, the indictment shows.

Edwards said the statute of limitations prevents authorities from prosecuting cases that go back further than five years.

A message seeking comment was left late Wednesday at the Cleveland office of Federal Public Defender Dennis Terez, who authorities say is representing Tuason.

Investigators said Tuason also sent threatening e-mails to office personnel at Jordache Enterprises.

The threats he's accused of are mostly alike, promising physical violence against black males associated with white women.

"Any blackie with a white girl is disgusting...Blacks should be shipped back to Africa," Tuason wrote, according to the indictment.

Wilson said threats were sent to places where the targets worked or may have attended functions.

"It's been a very long, enduring case," Wilson said. "Basically, it's a case we never gave up on."

Tuason was indicted on two counts of transmitting threatening interstate communications and six counts of mailing threatening communications. He was arrested on March 14.

Tuason is in the custody of U.S. Marshals. Each interstate communication charge carries a penalty of up to 10 years in prison and each mail charge carries a penalty of up to five years.