Two Baton Rouge companies pleaded guilty to money laundering charges Friday in a case that involves a small convenience store, millions of dollars in drug dealers’ cash and drug dealing by store employees.

The details that led to the convictions are contained in a May 2012 affidavit by Special Agent Andre Guilott of the Internal Revenue Service, who alleged Thang Minh “Tommy” Tran, 43, used the convenience store he founded to launder drug money.

Guillot also reported that an undercover agent purchased 1,000 tablets of Ecstasy from two store employees in 2010 as part of a joint Drug Enforcement Administration and IRS investigation. He said confidential informants also alleged Tran operated an illegal bookmaking business from the store — Quality Express, 1526 N. Foster Drive.

Guillot noted the little store deposited $178.5 million into a Hancock Bank account between July 2006 and December 2011.

Another $41.9 million was deposited at Dow Louisiana Federal Credit Union between June 2010 and December 2011, Guilott said in support of a request for a search warrant. He said Tran charged drug dealers and other customers one percent to convert their small bills to hundreds. Drug dealers were charged three percent for cash moved out of the state, the agent added.

But that business has ended, U.S. Attorney Donald J. Cazayoux Jr. said Friday, after corporate owners of the store pleaded guilty to felonies.

“This plea, along with (a) nearly $1 million money forfeiture here should send a clear message to any businesses which attempt to help drug dealers and any other criminals launder the proceeds of their illegal action,” Cazayoux said in a written statement.

Guillot, the IRS agent, wrote last year that money poured into the Hancock and Dow accounts moved out nearly as quickly as it was deposited. All but $400,000 of the combined total of $220.4 million at Hancock and Dow was withdrawn from the two accounts over the six-year period studied in the investigation, Guilott told U.S. Magistrate Judge Stephen C. Riedlinger.

Cash found in the two bank accounts as a result of the subsequent search totaled $992,462.

That money was forfeited as a result of plea agreements with Quality Express’ corporate owners, Katelyn & Claire Inc. and Alex T. Inc.

Katelyn & Claire President Trang Dang “Sabrina” Tran and that firm’s attorney, Andre Belanger, signed a plea agreement with Assistant U.S. Attorneys Jennifer M. Kleinpeter and J. Lane Ewing Jr. Sabrina Tran is Tommy Tran’s sister, according to Guilott’s affidavit.

Katelyn & Claire then entered a guilty plea to charges of conspiracy to launder money and failure to file federally required cash transaction reports for amounts in excess of $10,000.

Alex T., through President Sam Tran and attorney Lance C. Unglesby, pleaded guilty to the same charges and agreed to the same forfeiture. Sam Tran is identified in Guilott’s affidavit as brother of Tommy Tran and Sabrina Tran.

Each corporation could be sentenced to five years of probation and fined $500,000 or “twice the gain or loss resulting” from the money laundering scheme, court records show.

Tommy Tran pleaded guilty earlier to three counts of money laundering and one count of conspiracy to launder money. Each of those counts carries a possible prison term of 20 years and possible fine of $500,000.

Guilott also quoted the DEA undercover agent as saying Tommy Tran offered to sell him “30 to 40 pounds of ‘purple weed’ (marijuana) per week at $4,500 per pound.” Guillot also quoted the undercover agent as reporting that Tommy Tran stated “he sells Ecstasy at places like Louisiana State University and the University of Oklahoma.”

Two former store employees, brothers Son “Tattoo” Nguyen, 39, of Baton Rouge, and Thahn “Money” Nguyen, 30, of New Orleans, pleaded guilty earlier to illegal distribution of Ecstasy. They admitted that they sold 1,000 tablets of Ecstasy in the parking lot at Quality Express on Feb. 25, 2009.

The charge against the brothers carries a possible 20-year prison term.

Son Nguyen was sentenced by Chief U.S. District Judge Brian A. Jackson to 27 months in federal prison last month. Thahn Nguyen has not yet been sentenced.