TUCSON, Ariz. (AP) — The sister of former U.S. Supreme Court Justice Sandra Day O’Connor was killed a car crash Saturday in Arizona.

Ann Day, 77, suffered fatal injuries after her vehicle was struck by two other cars in the Tucson area, Pima County sheriff ’s spokesman Ryan Inglett said.

Day was a former Arizona Republican state senator and Pima County supervisor.

She was driving eastbound on Ina Road around 7:40 a.m. when an oncoming car crossed the median. Day’s vehicle was hit head-on, Inglett said.

A truck traveling behind Day then rear-ended her. Day was alone in the vehicle.

Paramedics transported Day to the hospital, where she was pronounced dead. The other two drivers, both male, were hospitalized with serious but non-life-threatening injuries.

Inglett said the Pima County Office of the Medical Examiner will determine the official cause of death.

Investigators were working to figure out what caused the first driver to cross the center line.

Meanwhile, condolences began to pour in from Arizona political figures.

“With Ann’s tragic death, our state has lost a tireless advocate who dedicated her life to public service – as a teacher, state senator and Pima County supervisor,” U.S. Sen. John McCain said in a statement.