As allegations of illegal operations within the company persist, Walmart’s Mexico and Central American subsidiary Walmex is seeing stock prices dive.

On Wednesday, Walmex shares fell more than 5 percent. The drop comes after the publication of a letter from U.S. Congressmen Elijah which suggested the Walmart Stores Inc. subsidiary had issues with money laundering and tax evasion.

In a letter to Michael Duke, the CEO of Walmart Stores, the Congressmen write, “We have obtained internal company documents, including internal audit reports, form other sources suggesting that Walmart may have had compliance issues relating not only to brubery, but also to ‘questionable financial behavior’ including tax evasion and money laundering in Mexico.” They added, “Although you have stated on multiple occasions that you intend to cooperate with our investigation, you have failed to provide the documents we requested, and you continue to deny us access to key witnesses.”

Cummings and Waxman , both Democrats, are ranking members of the Oversight and Energy committees of the U.S. House of Representatives.

While Mexican prosecutors have stated they would look into the allegations, no money laundering or tax evasion investigations have been announced. Also, Walmex had released a statement saying it has “no knowledge” or any investigation into the alleged issues by Mexican authorities.

Walmex operates a bank in Mexico and it is suspected of being one of the many used by drug cartels.

Add this to the bribery allegations from this past April and one has to wonder if Walmex employees are knowingly aiding the cartels of Mexico launder an estimated $10 billion each year.