Police are still trying to figure out why a man gunned down his ex-fiance outside a Chicago hospital and then murdered two others, including a police officer.

The gunman, Juan Lopez, had reportedly argued with his ex-fiance Dr. Tamara O’neal in the parking lot of the hospital before shooting her multiple times.

Lopez then ran inside where police say he killed resident pharmacist Dayna Less and officer Samuel Jimenez.

“She had a life,” said Brian Less, father of one of the victims. “She lived her life every day. She never stopped. And never stopped living. And we can all learn from her. Make the most of your life.”

Lopez was killed in the shootout. It’s unclear if he shot himself or if police killed him.

The Chicago Fire Department said that Lopez had been kicked out of the city’s Fire Department Academy four years ago after threatening a female cadet.