MINNEAPOLIS — Four days after a Minneapolis police officer fatally shot a woman who had called 911 to report a possible rape, the officer has yet to talk with investigators, and his attorney has given no indication he ever will.

Some legal experts say the move is wise and well within the officer’s rights. But without Officer Mohamed Noor’s version of events, there’s virtually no explanation for what happened Saturday when he fired a shot from the passenger seat of a squad car, past his partner in the driver’s seat and killed Justine Damond, 40, who was standing outside the vehicle.

Details that have emerged raised new questions Wednesday about whether proper police procedures were followed.

According to the state Bureau of Criminal Apprehension, Noor’s partner, Officer Matthew Harrity, told investigators he was driving in the alley with all of the vehicle’s lights off when he was startled by a loud noise, which authorities did not describe. Harrity said Damond appeared at the driver’s side window “immediately afterward” and Noor fired, striking her in the abdomen. She died at the scene.

Television station KSTP, citing a source it did not name, said the two officers thought they were being targeted for an ambush when they heard a pounding noise on the driver’s side. Noor had his gun on his lap, the station reported.

The Minnesota Bureau of Criminal Apprehension did not confirm the KSTP report. Harrity’s attorney, Fred Bruno, told the Star Tribune it was “certainly reasonable” for the officers to fear a possible ambush.

Assistant Police Chief Medaria Arradondo said that an internal use-of-force investigation has been opened, which is standard any time an officer discharges a weapon. The police chief has asked that the review be expedited, but much of the information needed is in the hands of state investigators.

Police did not respond to questions Wednesday about the internal investigation. Noor’s attorney, Thomas Plunkett, did not respond to interview requests from The Associated Press.

When it comes to talking to authorities, defense attorneys and legal experts said police officers have the same Fifth Amendment right against self-incrimination as everyone else.

“Any lawyer that would recommend to him that he should give a statement to the BCA should be disbarred,” said Joe Friedberg, a Minneapolis defense attorney who’s not involved in the case. “Nobody should ever speak to law enforcement when they’re the subject of a criminal investigation.”

The police department’s internal affairs unit can compel Noor to give a statement as part of its own investigation, and fire him if he refuses, but that statement cannot be used against him in any criminal investigation, Friedberg said.

In contrast, Officer Jeronimo Yanez in the nearby suburb of St. Anthony sat down with state agents last summer the day after he shot Philando Castile. Prosecutors used his statement as evidence against him during his manslaughter trial, but the defense used it too. Jurors apparently accepted Yanez’s claims that he saw Castile’s gun and believed his life was in danger. Yanez was acquitted.