The Gabels, both of Palatine, were identified on Friday night. John's wife, also an American, was wounded in the shooting on Thursday, April 24.
The three were part of a group at The Cure International Hospital in Kabul. Dr. Umanos was a pediatrician helping Afghan children wounded in the war and training a new generation of doctors. He worked at the Lawndale Christian Health Center on Chicago's West Side for 16 years before he and his wife, Jan Schuitema, moved to Afghanistan.
John Gabel worked for Morning Star Development and ran a health clinic at Kabul University, where he taught computer science classes in his spare time.
"We have lost a great man, a great teacher, a man who was here only to serve the Afghan people," Kabul University vice chancellor Mohammad Hadi Hadayati said.
Gary Gabel was in Afghanistan to visit his son. Hadayati said he had met them at lunch the day before the shooting.
The Gabel family went the next day to Cure hospital to meet Umanos.
The Interior Ministry on Saturday identified the alleged gunman as a police officer from Kabul's District 6. He shot himself in the stomach, but hospital officials saved his life.