LOS ANGELES—A former state assemblyman was arrested Monday on charges he committed bank fraud while working for the Los Angeles County Probation Department, marking the 39th arrest of a department employee in nine months, authorities said.

Probation Chief Jerry Powers warned that the arrest of executive manager Carl Washington, 47, will not be the last because he was hired to roll up his sleeves and "take care of some of the internal issues that are dragging the department's reputation through the mud."

Of the 39 employees arrested, 32 were sworn peace officers. In 20 cases, the charges were for serious crimes, including attempted murder, drug charges, fraud and drunken driving.

The department employs more than 5,800 employees, and the majority of them are glad there's a new focus on employee conduct, Powers said.

"They want me to get rid of these people," he said. "It's a small number of people who are impugning the department."

A message seeking comment was left after business hours Monday at the union representing probation officers.

The Probation Department has raised hiring standards, and prospective employees will undergo a polygraph test as part of their background screenings, Powers said. He also has requested 11 additional investigative and attorney staff to investigate problem employees more quickly.

Washington is charged with three counts of bank fraud and three counts of making a false statement to a federally insured financial institution.

Washington, a Democrat, represented the 52nd district in South Los Angeles from 1996 to 2002.

He is accused of applying for credit cards and loans, spending thousands of dollars with borrowed money and then falsely reporting to law enforcement that the credit cards were stolen and he was a victim of identity theft.

Prosecutors allege Washington then used police reports to wipe his credit reports of unpaid debts, and once the unpaid debts were cleared from his credit report, he would apply for new credit cards.

Each of the six counts carries a maximum penalty of 30 years in prison.