MINNEAPOLIS — The family of an Australian woman shot to death by a Minneapolis police officer has hired an attorney who represented the family of a black motorist, Philando Castile, who was also slain by a Minnesota police officer.

Minneapolis attorney Bob Bennett confirmed Thursday that he was representing the family of Justine Damond, who died Saturday night shortly after she called 911 to report a possible sexual assault in the alley behind her home.

Officer Mohamed Noor shot Damond, a 40-year-old life coach, once through the window of his police vehicle after she approached the car. Noor’s partner told state investigators that he had been startled by a loud noise right before the shooting. Noor has declined to be interviewed.

Bennett, who helped Castile’s family reach a nearly $3 million settlement with the suburb of St. Anthony, was in a deposition Thursday and not immediately available for an interview.

He told a Minneapolis TV station that Damond’s family in Australia is in disbelief.

‘‘She obviously was not armed, she was not a threat to anyone, nor could she have reasonably been perceived to be,’’ he told WCCO-TV. Bennett strongly disputed the suggestion from an attorney for Noor’s partner that the two officers might reasonably have feared an ambush.

‘‘I think that is ludicrous, that is disinformation,’’ Bennett said. ‘‘It doesn’t have any basis in fact.’’

Meanwhile, a ‘‘march for healing’’ was planned for Thursday evening for Damond.

Noor, with the department almost two years, can’t be forced to talk to the state Bureau of Criminal Apprehension. He will have to give a statement as part of his department’s internal investigation.

According to the state bureau, Noor’s partner, Officer Matthew Harrity, told investigators he was driving in the alley with 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.

The Minneapolis Police Department’s internal affairs unit can compel Noor to give a statement and fire him if he refuses, but that statement can’t be used in any criminal investigation, Friedberg said.

Assistant Police Chief Medaria Arradondo said an internal investigation has been opened, which is standard when 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.

Meanwhile, details that have emerged raised new questions about whether proper police procedures were followed.

KSTP-TV, citing a source it did not name, said the 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 said.

The 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.