WASHINGTON (AP) — The defining moment of a bizarre election season in the nation’s capital wasn’t provided by Mayor Vincent Gray or any of the seven Democrats trying to unseat him in next week’s primary. Instead, it came from the city’s top prosecutor.

U.S. Attorney Ronald Machen said this month that Gray knew about an illegal, $668,000 “shadow campaign” that helped propel him into office four years ago. Despite denials from the mayor, who has not been accused of a crime, the revelation further damaged an incumbent whose support had already eroded amid a long-running federal investigation.