Scott, Castile and the women who filmed their final moments

The officers were looking for a different man with an outstanding warrant when Scott exited the vehicle with a handgun in his hand and didn't respond to officers' orders to drop it, according to police.

Scott's family contends he was carrying a book.

Moments later, officers shot and killed Scott in an incident that his wife, Rakeyia Scott, captured on her cellphone camera from a short distance away.

Throughout the video, Rakeyia Scott can be heard telling police not to shoot her husband and that he is unarmed.

"Don't shoot him. Don't shoot him," she repeats forcibly, yet calmly.

"He doesn't have a gun. He has a TBI (traumatic brain injury)," Rakeyia Scott says. "He's not going to do anything to you guys. He just took his medicine."

With officers continuing to point guns at her husband, she begins to address him directly -- appealing to him with urgent rationale.

"Keith, don't let them break the windows," she says. "Come on out the car."

Rakeyia Scott goes on to say: "Keith, don't let them break the windows; come on out the car. Keith! Don't do it. Keith, get out the car. Keith! Keith! Don't you do it. Don't you do it. Keith! Keith! Keith!"

The video shakes, and for a moment, a man in bright blue pants is seen near the surrounded vehicle. Gunshots are heard as she says again, "Don't you do it."

She then yells: "Did you shoot him? Did you shoot him? He better not be (expletive) dead." Two people kneel over the figure with blue pants, apparently Keith Scott, now lying on the ground.

Although she is angry, she assures police that she will not approach them but will continue to record. She then asks if an ambulance was called.

A St. Anthony police officer pulled Diamond Reynolds and fiancé Philando Castile over in a routine traffic stop on July 6 in Falcon Heights, Minnesota.

Upon approaching the vehicle, Castile, 32, informed the officer that he had a permit to carry a weapon, according to Reynolds' account. The officer asked for Castile's license and registration and "as he was reaching for his ID in his back pocket," the officer shot Castile multiple times, she said.

What Reynolds did next seems counterintuitive. Instead of screaming in anger, crying in sorrow or comforting her four-year-old daughter Dae'Anna, who witnessed the ordeal from the backseat, she pulled out her cellphone and began live-streaming the events on Facebook.

In the video, Reynolds is clearly concerned for Castile, but remains calm as she follows Officer Jeronimo Yanez's orders and updates viewers on what led up to the incident.

"The officer just shot him in his arm. ... He just shot his arm off," she says matter-of-factly.

Actually, it's Yanez who appears to lose his cool.

"I told him not to reach for it! I told him to get his hand off it!" the officer shouts in panic. Later, he's heard shouting expletives.

"You told him to get his ID sir, his driver's license," Reynolds responds calmly. "Oh my god, please don't tell me he's dead. Please don't tell me my boyfriend just went like that."

Even after another officer orders Reynolds out of the car and instructs her to kneel, she remains cool.

"They threw my phone, Facebook," she tells viewers as it lies upward, recording the blue sky.

Reunited with her phone later in the back of a police cruiser, she summarizes the incident -- going so far as to point out the offending officer's appearance and the number of bullets fired. She even attempts to coordinate transportation for her and her daughter.

"Whoever can come to Larpenteur and Fry, that's where I'm at. I'm gonna need a ride home," she says.

When Reynolds finally screams in agony, her daughter comes to her comfort: "It's okay, I'm right here with you."

In both cases, viewers of the videos commented on how unnaturally calm Rakeyia Scott and Diamond Reynolds were in the midst of the deadly situations.

The women, however, are clear about their motivations, saying they wanted to expose police overreach and hold officers accountable.

"We want the public to take a look at this tape and see what was in the video before he was shot, and what was there afterward, and ask how it got there," Eduardo Curry, an attorney for the Scott family, said about Rakeyia Scott's decision to release the video and the debate over whether her husband was carrying a gun or book.

Reynolds made a similar statement in July. "I wanted it to go viral so the people could see" what happened, she said, explaining why she live-streamed the death of Castile. "I wanted everybody in the world to see what the police do."

"I want justice," she added.

Both shootings are under investigation.