Colorado tax preparer faked credentials and clients' returns, joins son and daughter behind bars

A 60-year-old Littleton man with an incarcerated son and daughter was sentenced Thursday to his own prison time for tax-related crimes. 

Thuan Bui, having earlier pleaded to a single count of Aiding and Assisting in the Preparation and Presentation of False and Fraudulent Tax Returns, was sentenced to three years in federal prison. 

Bui was initially indicted on 49 criminal counts by a federal grand jury in 2023. Internal Revenue Service investigators accused him of significantly understating his clients' tax liability on hundreds of tax returns during a five-year stretch starting in 2016, according to his plea agreement. 

Bui also told his clients he was a Certified Public Accountant. IRS investigators determined he has a bachelor's degree in accounting, but is not a CPA. 

Bui prepared almost 6,000 returns in those five years, per the indictment. Nearly 500 of them were found to have a Schedule C rent expense reduction which Bui falsely filed, often without supporting documentation. Of the first two dozen of those clients contacted by the IRS, eighteen of them required adjustments totaling more than $139,000. 

Investigators estimated the total loss in tax revenue to the U.S. government caused by Bui's actions to be more than $1 million. 

"This defendant willfully and repeatedly abused his clients' trust when his job was to help them accurately file their annual tax returns," Acting United States Attorney J. Bishop Grewell stated in a press release. "I encourage all taxpayers to be vigilant during the ongoing tax season to make sure their information is captured and reported accurately."

Bui's son, Kevin, was sentenced to 60 years in the Colorado Department of Corrections for his role in setting a fire that killed five people in 2020. Kevin Bui was one of three people convicted in the case. He admitted to planning to set the Green Valley Ranch home ablaze in retaliation for a stolen cell phone. 

However, he the others convicts mistakenly set the wrong house on fire. Two children were among those killed. 

Kevin Bui was 16 years old at the time.

During the investigation into the fatal fire, Denver police officers searched the Bui's Littleton home. In a basement bedroom, they found a plastic baggie containing fentanyl pills, a loaded gun, a loaded magazine, and more than $6,000 in cash. The bedroom's occupant, Thuan Bui's then-22 year old daughter, Tanya, was arrested. 

Investigators gained access to her social media accounts, exposing her drug dealings, some made through her younger brother, to adults and juveniles.

Tanya Bui pleaded guilty to drug charges and was sentenced to 130 months (10 years and 10 months) in federal prison. She is currently housed in West Virginia. 

Kevin Bui is currently staying in Colorado's Arkansas Valley Correctional Facility in Ordway.

The judge presiding over Thuan Bui's sentencing recommended he be sent to a federal prison in Colorado or neighboring state.