Washington ? A scientist who allegedly tried to sell classified secrets to Israel had worked on the U.S. government’s Star Wars missile shield program, and the Justice Department declared Tuesday that he had tried to share some of the nation’s most guarded secrets.

Arrested in an FBI sting operation, Stewart David Nozette was jailed without bond and accused in a criminal complaint of two counts of attempting to communicate, deliver and transmit classified information.

Had he succeeded in passing classified information, Nozette would have done grave damage to the nation’s security because the information he possesses includes “some of our most guarded secrets,” assistant U.S. Attorney Anthony Asuncion said in court. He did not elaborate.

Nozette, looking disheveled after spending the night in jail following his arrest Monday, gave his name to U.S. Magistrate Judge Deborah Robinson, but otherwise he did not speak.

If convicted, the 52-year-old scientist most likely would have to spend the rest of his life in prison and there is a substantial risk that he would flee now if allowed to remain free, the federal prosecutor told the magistrate. The next court proceeding in the case was scheduled for Oct. 29.