The initial test results on the substance were inconclusive, the person said, though authorities don’t believe the powder is deadly. The person added that Trump Jr.’s life is not in jeopardy.

The Palm Beach County Sheriffs Office is assisting the Secret Service in the investigation, said Teri Barbera, spokesperson for the department.

Trump Jr., the eldest son of former President Donald Trump, has long been a high-profile surrogate for his father. He is a regular guest on conservative media programs, and recently campaigned in New Hampshire ahead of the state’s January primary.

Kimberly Leonard contributed to this report.