A 30-year veteran of the State Department has to pay a $5,000 fine for illegally peeking at passport files of famous Americans.

Gerald Lueders of Woodbridge, Virginia also was sentenced Wednesday to one year's probation for looking at more than 50 of the confidential files for celebrities, politicians, media figures and acquaintances.

Prosecutors said "idle curiosity" drove the 65-year-old, who otherwise had a distinguished career at the State Department as a foreign service officer and contract employee.

The investigation began in March 2008 after authorities discovered unauthorized access of the files for then-presidential candidates Barack Obama, John McCain and Hillary Rodham Clinton.