(WASHINGTONPOST) — Fairfax County Public Schools discovered the administration mistakenly hired seven employees who are convicted felons, including a high school teacher who was once part of a trafficking ring that conspired to import more than a kilogram of heroin.

School officials uncovered the mistake during a comprehensive search of hiring records that began in 2012 after a Madison High School special education teacher inquired whether her 1992 conviction for drug trafficking would stall her promotion to an administrative position.

That employee, Deilia Butler, joined Fairfax schools in 2006. She had stated truthfully that she was a convicted felon on her application. So did the other six employees, school officials said.

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