A former employee of the District’s tax office admitted in federal court Wednesday that she participated in a scheme that involved filing fraudulent federal and local tax returns and netted $14.7 million in refunds.

Kimberle Y. Davis, 44, pleaded guilty to conspiracy and first-degree theft. Federal prosecutors said that Davis worked part-time in 2009 and 2010 for 2FT Fast Facts Tax Service, a tax preparation business in the District, and took part in filing just over 1,000 false federal and local returns the netted about $4 million in refunds.

The five-year scam started in 2006, federal prosecutors said, and involved nearly 3,700 fraudulent returns.

While helping file the false returns, Davis also used her position at the D.C. Office of Tax and Revenue to check government computers to see if 2FT clients were being audited.

“Kimberle Davis’s participation in this massive tax fraud is especially troubling because she worked for the D.C. Office of Tax and Revenue,” said U.S. Attorney Ronald C. Machen in a statement. “She should have been promoting the integrity of our tax system, but instead used her expertise to help more than 1,000 clients avoid paying their fair share.”

No sentencing date has been set. Davis faces a likely sentence of between 37 and 46 months under federal guidelines, prosecutors said.