Officer Harrity, who did not fire his gun and is not charged with a crime, has said he heard a loud noise and sensed a figure approaching the cruiser on his side of the car. “We both got spooked,” he told a supervisor.

Officer Noor, who has since been fired by the Police Department, has never spoken with investigators about what happened or why he pulled the trigger. His silence is a rarity: Police officers involved in shootings, including the relatively few who are ultimately charged with crimes, almost always tell their account of what happened to their police departments.

The uncertainty has left people reaching their own conclusions, often disparate ones that have created new rifts on top of old ones. In Australia, where gun violence is comparatively rare, the case stirred outrage. In the tree-lined Fulton neighborhood of Minneapolis, it remains a source of anger.

“I can’t imagine what Justine was doing or would have done that would cause Officer Noor to go from zero to shoot in such a short period of time,” said Todd Schuman, who lives about a block from Ms. Ruszczyk’s home, and who is part of an activist group that pushed for charges against the now former officer.

But others said they believed the charges in the case of Ms. Ruszczyk, who was white, revealed a double standard when it comes to such prosecutions.

“I do not believe that if the victim had been Somali or a person of color, that this officer would have been charged,” said Nekima Levy Armstrong, a civil rights lawyer who used to lead the Minneapolis N.A.A.C.P., and who protested the police shootings of Jamar Clark and Philando Castile, both of whom were black.