SMITHFIELD — The Johnston County school system has fired a teacher’s assistant at Smithfield Selma High School who was charged with several federal drug trafficking offenses, including selling heroin at the school.

Winston Antonio Evans, 29, was indicted by a federal grand jury last week on four counts of distributing heroin, including one count of distributing the drug “in, on and within 1,000 feet” of the high school.

Evans also was charged with one count of possessing a firearm “in furtherance of a drug trafficking crime.” The U.S. Attorney’s Office announced the indictments Wednesday.

The school system suspended Evans with pay on Wednesday when it learned of the charges. On Thursday school officials announced that he had been fired.

Evans has worked for the Johnston County school system since April 10, 2008. Prosecutors say the offenses took place in February and March of this year.