Lorraine Gerson, an assistant U.S. attorney in Newark who was the nation’s oldest-serving federal prosecutor, died Monday at age 89.

Gerson, who handled financial crimes and fraud cases for four decades at the U.S. Attorney’s Office, kept on working far past the age when most other people retire. Although she took leave late in 2018 to battle cancer, U.S. Attorney Craig Carpenito said Gerson prosecuted more defendants for the year than most other assistant U.S. attorneys in the office.