Federal prosecutors say a former National Security Agency contractor faces up to five years in prison after pleading guilty to filing timesheets for hours not worked.

The U.S. Attorney’s Office says Ann Warwick of Columbia falsified documents for more than 150 days and submitted pay sheets for 57 days she did not work. Prosecutors said she was paid $132 an hour for 836 hours she did not work. Prosecutors say the false filings cost the government more than $108,000.

Prosecutors say the 46-year-old Warwick is scheduled to be sentenced Aug. 31. She entered the plea on Friday.

The NSA is based at Fort Meade, south of Baltimore.