SYDNEY, Australia — Officials in Minneapolis said on Thursday that Justine Damond, an unarmed Australian woman killed last weekend by one of the city’s police officers, should not have been shot. The police were responding to a 911 call by Ms. Damond, who had reported an episode she said she feared was a sexual assault.

Here are some major questions the case presents:

Why doesn’t the officer have to testify or talk about what happened?

Mohamed Noor, 31, the officer who fired the shot that killed Ms. Damond, declined to be interviewed by investigators. His lawyer has not indicated when, if ever, that would happen. The state agency investigating the shooting said that under the law, it cannot compel the officer’s testimony. As citizens, police officers have the same Fifth Amendment right to remain silent, experts said.

Minneapolis Police Chief Janeé Harteau said on Thursday that she hoped Officer Noor would share his version of events with investigators. “There are questions that need to be answered,” she said. “And he’s the only one who has those answers.”

Why was the officer’s body camera not on? Is that typical?

During the shooting on Saturday, neither Officer Noor nor his partner, Officer Matthew Harrity, had their body cameras activated when they encountered Ms. Damond, 40, in an alley behind her home. The dashboard camera of their squad car was also off. Officer Noor may have violated department policy by not turning on his body camera before firing his weapon.