Thuy Tien Le, 40, pleaded guilty last week in federal court to preparing false income tax returns and committing wire fraud. She admitted that she did so while running her Fair Oaks-based, tax-return preparation business called T2 Advantage Services LLC.

She was convicted last Wednesday, April 30, in U.S. District Court in Alexandria. As a result, when she returns for sentencing on July 18, she could receive a possible maximum of three years in prison on the tax charge and 20 years behind bars for the wire-fraud offense.

In a statement of facts filed with her plea agreement, Le, now of Sterling, admitted that, from 2005 through 2013, she owned and operated her business out of her home on 12808 Madeley Court in Fairfax. She prepared federal income-tax returns for her clients and led them to believe she’d electronically filed legitimate returns with the IRS.

But before filing these returns, she altered them by adding false itemized deductions so she could generate large income-tax refunds. But instead of this money going to her clients, it went into her own pockets.

Le admitted to federal authorities that she prepared and filed false income tax returns in this manner for at least 50 clients, without their knowledge or consent, and that she had these refunds deposited electronically into her own bank accounts. She further admitted that the IRS sustained $454,455 in losses because of what she’d done.

The investigation into her suspected criminal activities began in early July 2013 when Fairfax County police received a report from a resident that Le had prepared their income taxes. That person received the prepared documents, including a statement indicating exactly what federal and state refunds to expect.

Shortly thereafter, say police, the resident “was in the process of refinancing [his or her] mortgage and discovered that the tax documents the mortgage company obtained from the Internal Revenue Service were different than the ones Le provided to [him or her].”

Detectives, working with IRS special agents, were eventually able to piece together the details and extent of Le’s illegal actions. Police arrested her Aug. 6, 2013, and charged her with one count each of money laundering and obtaining money by false pretenses, plus two counts of identity theft with intent to defraud.

Her case was later turned over to federal authorities. Assistant U.S. Attorney Paul J. Nathanson is prosecuting the case in court and, last Wednesday, April 30, in U.S. District Court in Alexandria, Le entered her guilty pleas before Judge Claude Hilton.