A sworn police statement said city money went to Hixon and her relatives; the man she lived with and his relatives; and co-workers at a development company where the mayor also worked.
The police statement, released by prosecutors, showed the investigation grew to include a "concerned citizen" wearing a hidden recorder during a conversation in which Hixon admitted to illegal conduct, told the person what to say to police, and paid the man $525 to "keep him quiet."
Hixon turned herself in to authorities Wednesday in a negotiated surrender and was released on bond without having to spend the night in jail before her court appearance.
No one else has been charged, authorities said, but an investigation continues and Hixon agreed to cooperate. Christensen said she testified to a grand jury after pleading guilty.
Residents who long suspected of wrongdoing in the town began talking to police after word of the investigation leaked earlier this year, said the district attorney. While Hixon was old, he said, she also was powerful.
"We had quite a few citizens come forward with information they had held on to for years," Merrell said. "They were reluctant to do so earlier for fear of being ostracized or because it was a proverbial 'little old lady.'"