-- Federal authorities believe they discovered a plot to either kill a federal prosecutor or destroy evidence against two Lebanese brothers convicted of aiding the Lebanese militant group Hezbollah, a newspaper reported today.

The target of the alleged plot was First Assistant U.S. Attorney Kenneth Bell, the Charlotte Observer reported.

FBI agents suspect one of he brothers, Mohamad Youssef Hammoud, wrote a letter to an informant outlining a plot to kill Bell or blow up government evidence, according to newly unsealed court documents.

The letter allegedly suggested that someone be brought in to carry out the plot.

"His assignment is to put bullets into the skull of the arrogant . . . prosecutor or to annihilate with massive explosives the evidence against us," the letter said.

Hammoud and his brother, Chawki, were convicted in June of federal charges of helping to run a cigarette-smuggling operation that funneled profits to Hezbollah, one of the groups the United States has designated as foreign terrorist organizations.

Bell was the prosecutor handling the case.

Hammoud has not been charged in connection with the alleged plot, but prosecutors intend to try to introduce evidence about it during his sentencing hearing, expected in the next few months.

Hammoud, 29, could spend the rest of his life in prison. The letter was among more than 250 pages of documents that were unsealed in recent weeks.

Hammoud's attorney, Deke Falls, has accused FBI agents of illegally obtaining evidence about the alleged plot. He also attacked the credibility of the informant, accusing him of fabricating the letter.

Falls contended that the informant had failed a lie detector test and had an incentive to help the government because of his impending deportation.

Prosecutors acknowledge there were credibility problems with the informant, who has had numerous convictions. However, responding to defense allegations, prosecutors wrote, "It is not disputed that a letter was written in defendant's own hand putting out a contract to destroy evidence and kill the prosecutor."

Authorities received a tip about the alleged plot from an inmate who was in the Mecklenburg County jail at the same time as Hammoud. The informant contacted authorities about the alleged threat to the prosecutor.