The Duong family owns the city’s recycling company, California Waste Solutions. In the subpoena, investigators specifically name the company’s CEO, David Duong, and his son, Andy Duong.

The FBI and U.S. Attorney’s Office remain tight-lipped about what — and who — their investigators are investigating. When asked about the grand jury’s subpoena on Tuesday, a USAO spokesperson told KRON4, “I am not permitted even to confirm the existence (or non-existence) of a grand jury investigation.”

In a 1-on-1 interview with KRON4 last week, Thao maintained her innocence. The mayor also asserted that she is not the subject of the federal investigation.