A federal grand jury has launched a sweeping investigation of Oregon Gov. John Kitzhaber (D) and fiancée Cylvia Hayes, the Oregonian reports.

“The subpoenas shed light on what looks to be the largest criminal investigation of a public official in Oregon… Investigators are after any state record mentioning Hayes, her private consulting business and her role in the governor’s office. They want her personal tax returns and those of her company dating back to 2009. The state also must turn over records of her use of state credit cards.”

Kitzhaber announced he would resign from office next week.