USPlabs, the seller of the best-selling workout supplement Jack3d and OxyElite Pro, is having a hard time facing a crackdown imposed by the U.S. Justice Department.

The federal officials announced Tuesday about the department's decision to file criminal charges against the firms that sale their nutritional supplements unlawfully. In addition, the officials announced that the department will conduct a larger probe aimed at identification of unproven products and firms that falsely claim that their supplement could help build muscles, lose weight or reduce drug addiction.

The U.S. Department of Justice, along with its federal partners, has filed criminal and civil cases against more than 100 marketers and makers of dietary supplements, including USPlabs. The action enforces by the department is the result of the investigation it carried out in the last one year.

In each identified case, either the department or its federal partner alleges that the dietary supplement contains some other ingredient, then what is mentioned on the label of the product In some cases, the product fails to meet the health benefit claim being made by the company because of lack of any scientific evidence.

Allegedly, USPlabs told some retailers that its products contain natural plant extracts. However, it was found that it actually contains a synthetic stimulant, obtained from a Chinese chemical factory. According to the federal complaint, four company officials were arrested on the account of unlawful selling and two more are expected to surrender.

“This joint agency effort is a testament to our commitment to protecting consumers from potentially unsafe dietary supplements and products falsely marketed as dietary supplements,” said Deputy Commissioner Sklamberg, in a press statement. “The criminal charges against USPlabs should serve as notice to industry that if products are a threat to public health, the FDA will exercise its full authority under the law to bring justice.”