Sen. Claire McCaskill (D-MO) took aim at opioid drugmakers’ marketing programs, launching an investigation looking at what role corporate pharmaceutical marketing played in the opioid epidemic.

McCaskill, as the ranking Democrat of the Senate Committee for Homeland Security and Governmental Affairs, formally launched a probe into five manufacturers of opioids in the U.S. — Purdue Pharma, Johnson & Johnson, Insys Therapeutics, Mylan and Depomed  — to investigate what strategies these companies allegedly employed to promote opioid use.

See also: Campaign seeks to educate doctors about when to prescribe opioids

In a letter, McCaskill wrote that the opioid epidemic is a “direct result of a calculated sales and marketing strategy major opioid manufacturers have allegedly pursued over the past 20 years.” On average, 78 people die from an opioid-related overdose everyday in the U.S., according to the Centers for Disease Control and Prevention.

Specifically, she demanded from the companies the direct-to-consumer and physician marketing plans that were developed during the last five years. The committee is also requesting information about whether there were quotas for opioid sales reps to recruit physicians for speaker programs, and if these drugmakers contributed to certain third-party patient advocacy organizations.

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Continuing medical education programs, too, fell under the investigation’s remit. The letter asked for information showing evidence of funding for “CME modules or other education presentations” directed toward healthcare providers since January 2012 as well as copies of any the materials given out in those presentations. The committee requested all documents by April 27.

Several opioid drugmakers have recently launched educational campaigns about how to responsibly use and prescribe opioids. Purdue developed a website in 2015 to inform healthcare stakeholders about their role in stopping opioid abuse. And, last year, Teva Pharmaceutical Industries launched a video series, Pain Matters, with a similar goal: to educate patients and providers about responsible pain management.