Federal prosecutors in California are conducting a criminal probe into e-cigarette manufacturer Juul, The Wall Street Journal reports. The probe by the U.S. Attorney’s Office for the Northern District of California is in its early stages, the Journal reports, and it is unclear what it is focusing on. A spokesman for Juul had no immediate comment for the newspaper, and the U.S. attorney’s office could not confirm or deny the investigation.

The probe comes as the Federal Trade Commission, the Food and Drug Administration, and a number of states are investigating the company, with a focus on its marketing and the product’s nicotine content. The Trump administration is also considering banning e-cigarettes. On Monday, Kansas officials announced the second death in the state linked to vaping, marking the ninth death nationwide that has been connected to e-cigarettes.