Efforts to reach Patton were unsuccessful on Friday.
The charges allege that when Patton worked in the "scale house" collecting fees for dumping refuse at the landfill, 6030 W. California Ave., she developed a scheme that defrauded the county of thousands of payments in a six-month period between April 20, 2012, and Oct. 27, 2012.
In a probable-cause statement, District Attorney's Office Investigator Michael Leary alleged that Patton often printed "duplicate tickets" when a customer paid at her window.
Patton then allegedly cut the words "Duplicate Ticket" off the duplicate receipts she kept. When a new customer came up who paid in cash, the charges allege, she would hand back an altered duplicate ticket and put the money in the till, but would not enter the transaction into the computer system.
The charges contend Patton kept track of how much money was not entered into the computer system and, at the end of the day, would "consult her notes of how much unaccounted for cash was in the till and remove it to her own pocket."
She did it frequently, the district attorney's office alleged.
"Evidence shows Patton to have printed and altered at least 2,200 duplicate receipts, government documents, and passed them on to customers," Leary wrote, noting that on two days alone June 2 and June 23, 2012 "Patton provided 185 altered duplicate receipts to customers entering the solid waste facility."
County Public Works Director Russ Wall, who oversees the waste facility, said complaints by other employees led to a probe of agency books by county auditors and attorneys.
"They could see there was something fishy," he added, noting that a "meticulous" yearlong investigation uncovered Patton's alleged scheme and led to reforms.
"Once the method of fraud was discovered people always try to find holes in your system we immediately took steps to safeguard our cash transactions," Wall said, citing a ban on printing duplicate receipts and installation of better tracking software.
"You're never 100 percent sure," he added, "but we're confident there's no continued illegal activity going on."