The email that Joe Hagood received in August 2017 was vague and brief, but too unsettling to ignore.

Hagood worked at Medpace, a Cincinnati company that tests new drugs for pharmaceutical manufacturers. His job was to supervise the independent research centers that Medpace pays to handle the nitty-gritty of human trials: finding volunteers, dispensing medications, tracking side effects. The author of the unsettling email, Justina Bruinekool, was a staffer at one of those centers. She claimed to have an urgent reason for writing: Her employer was fraudulently conducting a major trial that Hagood was overseeing.

The email contained no evidence to support this jarring allegation, so Hagood thought it wise to tread cautiously; he worried that Bruinekool might be a disgruntled employee out to make trouble. In his reply, he thanked her for the tip and politely encouraged her to reach him on his cell phone.