By Brad Parks, Emanuella Grinberg, Faith Karimi and Steve Almasy

CNN

MINNEAPOLIS (CNN) -- A Minneapolis police officer said he was startled by a loud sound near his squad car before his fellow officer shot dead Justine Ruszczyk, state investigators said.

Officer Michael Harrity has talked to state investigators, the Bureau of Criminal Apprehension said.

Officer Mohamed Noor, who was in the car with him and fired the weapon in the fatal shooting Saturday, has exercised his constitutional right not to speak to state investigators, the Minnesota Bureau of Criminal Apprehension said Tuesday.

It's unclear if or when he will.

"He has a story to tell that no one else can tell," Minneapolis Mayor Betsy Hodges said Tuesday. "We can't compel him by law, but I wish that he would make that statement."

Investigators also want to talk to a man on a bicycle who watched police perform CPR on Ruszczyk, and are asking him to come forward.

Family sees documents

City Council member Linea Palmisano said some documents from the case have been shared with Ruszczyk's family, and will be released online Wednesday morning.

A preliminary investigation determined Noor fired at Ruszczyk from the passenger seat of his police vehicle.

The officers turned on body cameras after the shooting; the squad car camera was never turned on. The police department has opened an internal affairs use of force review, authorities said.

Months of investigations

The department's BCA investigation is expected to last two to four months, said Chuck Laszewski, a spokesman for the Hennepin County attorney's office.

Once that happens, county attorney Mike Freeman -- not a grand jury -- will decide whether either of the two officers involved should be charged in Ruszczyk's death.

Officers on leave

Harrity was driving and Noor was in the passenger seat as they drove through the alley looking for a suspect, according to the Bureau of Criminal Apprehension. The squad lights on their vehicle were off.

Harrity told investigators that as they drove down the alley, he was startled by a loud sound near the squad car. Immediately afterward, Ruszczyk approached the driver's side window and Noor fired his weapon, striking Ruszczyk through the driver's side window, Harrity told the BCA.

The officers exited the vehicle and provided medical attention, but Ruszczyk was pronounced dead at the scene.

Both officers are on administrative leave.

Body camera policy reviewed

Minneapolis police policy says body cameras should be turned on prior to use of force "as soon as it is safe to do so" and during "any contact involving criminal activity."

The officers turned on their cameras after the shooting and the squad car camera was not turned on, according to the BCA.

But the department is currently in the process of rolling out body cameras to all units and officers, and an updated policy is forthcoming, Minneapolis Assistant Police Chief Mederia Arradondo said Tuesday.

The department was eight months away from a full department-wide rollout, he said. By next month, mandated supervisor training will be completed throughout the department; front line supervisors have been tasked with ensuring officers increase the activation of their body cameras, he said.

Meanwhile, the department has opened an internal affairs use of force review, he said. It's on hold while the BCA has custody of evidence for its investigation.

The mayor lamented the lack of body camera footage, but called for patience as the investigation continues.

"The information the BCA has shared today gets us closer to having answers, closer to seeing justice done. And we do have more information now, though it's frustrating to have some of the picture, but not all of it," she said.

" ... Body cameras are a very powerful tool, not an infallible tool, but a powerful one that have proven useful in our investigations."

Officer sends condolences

Both officers have been identified by their attorneys. Noor offered his condolences to Ruszczyk's family in a statement from his attorney.

"He takes these events very seriously because, for him, being a police officer is a calling," attorney Tom Plunkett said in the statement. "He joined the police force to serve the community and to protect the people he serves. Officer Noor is a caring person with a family he loves and he empathizes with the loss others are experiencing."

Plunkett said he and his client "would like to say more, and will in the future ... however, there are several investigations ongoing and Officer Noor wants to respect the privacy to the family and asks the same in return during this difficult period."

Grief in two countries

Ruszczyk, 40, was originally from Australia but moved to the United States in 2014. She was living with Don Damond, her fiancé, at the time of her death. They were planning to marry in August.

"It is difficult to fathom how to go forward without her in my life," Damond said Monday. "Our hearts are broken and we are utterly devastated by the loss of Justine."

Halfway around the world, Ruszczyk's father made an emotional plea for justice.

"Justine, our daughter was so special to us and to so many others," John Ruszczyk told journalists in Australia. "Justine was a beacon to all of us. We only ask that the light of justice shine down on the circumstances of her death."

Ruszczyk has dual citizenship in the United States and Australia because her father holds US citizenship, a source who knew her said. The country's Department of Foreign Affairs and Trade said it is providing consular assistance to the woman's family.

"The death of Justine is a loss to everyone who knew her. She touched so many people with her loving and generous heart," Damond said. "Our lives are forever changed as a result of knowing her. She was so kind, and so darn funny. She made us all laugh with her great wit and her humor."

Ruszczyk trained as a veterinarian and later became a yoga instructor and life coach.

Brad Parks reported from Minneapolis; Emanuella Grinberg, Steve Almasy and Faith Karimi reported and wrote from Atlanta. CNN's Dave Alsup contributed to this report.