(Reuters) – Federal prosecutors in California are conducting a criminal probe into e-cigarette maker Juul Labs Inc, the Wall Street Journal reported on Monday, citing people familiar with the matter.

The focus of the probe by the U.S. attorney’s office of the Northern District of California, which is in early stages, was unclear, the report said.

The company, in which tobacco giant Altria group <MO.N> owns a 35% stake, is facing a regulatory crackdown and increased government scrutiny in the domestic market as teenage use of e-cigarettes surges.

Six deaths have been linked to vaping and U.S. public health officials are investigating 450 cases of potential vaping related lung illness across 33 states and one U.S. territory.

North Carolina Attorney General Josh Stein said in a lawsuit in May that the company marketed its products to minors and downplayed risks. Other state attorneys general along with the U.S. Federal Trade Commission are investigating Juul’s marketing practices.

The U.S. Food and Drug Administration earlier this month warned Juul over marketing its products as safer than traditional cigarettes and requested documents and information within 30 days from the letter.

Meanwhile, the Trump administration has announced plans to remove all flavored e-cigarettes from store shelves in a widening crackdown on vaping.

A spokesman for the attorney’s office and Juul declined to comment.

Shares of Altria were trading marginally lower at $40.67 after the closing bell.

(Reporting by Manas Mishra in Bengaluru; Editing by Arun Koyyur)