Federal prosecutors in California have launched a criminal probe into e-cigarette company Juul amid a nationwide epidemic of vaping-related illnesses, a new report claims.

The scope and focus of the investigation by the US Attorney’s Office for the Northern District of California is unknown, but comes as the San Francisco-based startup confronts increased scrutiny from authorities, The Wall Street Journal reported Monday.

At least eight people have died from vaping, while more than 500 others have fallen ill with mystery lung issues, according to The Centers for Disease Control and Prevention.

The probe is the federal criminal investigation and comes after the Trump administration last week announced a crackdown on flavored e-cigarettes — arguing they are too appealing to kids.

Juul maintains it has never marketed its product to minors. A spokesperson for the company on Monday had no immediate comment on the WSJ report.

Rates of teen vaping doubled from 2018 to 2019 — with 25% of high school seniors admitting to using an e-cigarette in the past month, a National Institute on Drug Abuse study found.

The Federal Trade Commission and the Food and Drug Administration are already investigating Juul’s marketing practices — with FDA tobacco director Mitch Zeller stating Thursday, “We are in desperate need of facts.”

The FTC probe is focused on whether Juul used social media celebrities to appeal to minors, WSJ reported.

Last week, New York became the first state to ban the sale of flavored e-cigarettes with the exception of menthol and tobacco flavors.