SALEM, Ore. — Oregon Gov. John Kitzhaber announced his resignation Friday over a deepening influence-peddling scandal surrounding his fiancee and on the same day the U.S. Attorney’s Office issued a subpoena demanding records and electronic communications pertaining to the pair.

The subpoena was the first acknowledgment of a federal investigation against Kitzhaber and Cylvia Hayes. It marks yet another turn in a scandal that brought down Oregon’s longest-serving chief executive.

Kitzhaber’s resignation, which is to take effect Wednesday, cleared the way for Secretary of State Kate Brown to assume Oregon’s highest office and become the nation’s first openly bisexual governor.

Kitzhaber insisted he broke no laws.

“Nonetheless, I understand that I have become a liability to the very institutions and policies to which I have dedicated my career and, indeed, my entire adult life,” he said in a statement.