Krishnamoorthi, who is the Chairman of the Oversight Subcommittee on Economic and Consumer Policy, sent a letter to Juul CEO Kevin Burns on Friday asking the company for internal records regarding Juul’s communications, and social media and advertising practices.

The committee also seeks information about Juul’s long-term impact on users’ health, and documents related to its business deal with tobacco giant Altria, which purchased a 35% stake in Juul last year.

The latest investigation launched the same week as a California Democratic Party convention in San Francisco, where Juul was listed as a major sponsor. Juul’s sponsorship, among other corporate sponsorships, caused disagreements between some party members.

Acting party chair Alexandra Gallardo-Rooker said the party should not turn down money from the e-cigarette maker because “it takes a lot of money to run this party and make sure we win.” But Hene Kelly, the party director for California’s Region 6 called out the sponsorship, arguing that the company “preys on children.”

In a later interview, Kelly said the Democratic Party should not be accepting that kind of money, instead calling for financial support of the party “to be ethical, to be for the people, [and] not to hurt the people.”

Rep. Krishnamoorthi’s office did not immediately respond to a request for comment.

The congressman cited research from the Centers for Disease Control and Prevention in his June 7 letter to the company. According to CDC research, the rate of e-cigarette use among high school and middle school students spiked by 78% and 48%, respectively, in just one year from 2017 to 2018.

“The safety and well-being of America’s youth is not for sale,” Krishnamoorthi wrote. “I am extremely concerned about reports that Juul’s high nicotine content is fueling addiction and that frequent Juul use is sending kids across the country into rehab, some as young as 15.”

Krishnamoorthi’s probe is the latest action taken by Democrats against the e-cigarette company. Nearly a dozen Democratic senators sent a letter to Juul in April asking about its marketing practices and its deal with Altria.

A spokesperson for Juul told Fortune the company shares “the subcommittee’s concerns about youth vaping and welcome the opportunity to share information about our aggressive, industry leading actions to combat youth usage.”

The statement continued: “We look forward to a productive dialogue as we continue to combat youth usage and help adult smokers switch from combustible cigarettes, which remain the leading cause of preventable death around the world.”

The Food and Drug Administration (FDA) last year conducted a surprise inspection of Juul Labs’ San Francisco headquarters, and seized “thousands of pages of documents” related to the company’s marketing strategy.

Juul has been criticized for targeting teenagers in its advertising efforts, paying social media influencers to promote their products on Twitter, Instagram, and Facebook. The company has also received backlash for targeting younger users with its fruit-flavored pods, which can now only be purchased online. More recently, Juul has backed legislative efforts to raise the national smoking and vaping age from 18 to 21.

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