Sunday morning was meant to be a girls outing for the Gilliams, as cousins, sisters, aunts and nieces piled into an SUV to go get their nails done together in suburban Denver.

But before they could even find an open salon, the family’s four children were ordered at gunpoint to lie facedown on the parking lot, and two were handcuffed. The Black girls, who range from 6 to 17 years old, broke down into tears and screams as a group of White police officers hovered over them.

“I want my mother,” one of them can be heard wailing on a video of the incident, gasping for air between sobs. “Can’t I have my sister next to me?”

Aurora’s police chief apologized on Monday night and launched an internal investigation after video of the incident quickly went viral. Police blamed a misunderstanding: The license plate number on a stolen motorcycle matched the family’s blue SUV, and that car had been reported missing earlier this year, too.

But Brittney Gilliam, who had been driving her relatives to the salon, said the mix-up did not justify forcing her young relatives onto the pavement or putting two of them, ages 12 and 17, in handcuffs. She has since filed a complaint.

“That’s police brutality,” she told KUSA. “There’s no excuse why you didn’t handle it a different type of way. … You could have even told them, 'Step off to the side let me ask your mom or your auntie a few questions so we can get this cleared up.’ ”

Sunday’s confrontation, which had been viewed more than 1.4 million times on Twitter as of early Tuesday, marks another troubling incident for a police department that has already drawn intense scrutiny over its treatment of Black people.

Nearly one year ago, Aurora police tackled 23-year-old Elijah McClain as he was walking down the street and placed him into a chokehold, just moments before paramedics injected the Black man with a heavy sedative. Last month, two officers were fired over photos reenacting the violent arrest near a memorial for McClain, who died days later.

Following a national outcry in recent weeks, Colorado Gov. Jared Polis (D) has ordered an independent review of the man’s death.

The latest troubling incident for the Aurora Police Department began just before 11 a.m. Sunday, when police were notified about a possible stolen vehicle near a strip mall on Aurora’s Iliff Avenue, they said in a statement. Officers dispatched to the scene found a vehicle matching the physical description and license plate number they had been given.

A few yards away, the Gilliam family discovered the nail salon they were hoping to go to was closed. As Brittney and another adult relative loaded the four girls back into the SUV, police approached the car from behind with their guns drawn.

As an adult in the family was led away and questioned, officers handcuffed two of the girls and ordered all four to lie facedown on the parking lot beside the car.

Jennifer Wurtz, a bystander who filmed the incident, shouted to police that the girls were scared and asked to be able to speak to them, she told KUSA. But the officers refused, telling her to back up 25 feet to avoid interfering.

After about a minute, an officer crouched down to ask the children, “Can I get you guys off the ground?”

“Yes, I want to get off,” one of them responds through tears. He helps the two girls in handcuffs, 17 and 12, sit up but leaves them with their hands restrained behind their backs.

In a statement Monday, Aurora police said the officers may have gotten mixed up because the family’s SUV had been reported stolen earlier this year. (Gilliam had in fact contacted authorities in February, she told KUSA, though her vehicle was found the next day.)

Police also clarified another vehicle bearing the same license plate number as the Gilliam’s car was reported stolen on Sunday. That vehicle was a motorcycle from Montana, the Associated Press reported.

Aurora police said officers are trained to perform a “high-risk stop” when stopping a stolen car. The tactic involves drawing weapons, telling passengers to exit the vehicle and ordering them to lie on the ground.

Faith Goodrich, a spokeswoman for the police department, told KUSA there is no written policy about when and how to use the stop, which is also used when officers know or suspect people in a car are armed.

The department’s interim chief, Vanessa Wilson, said police officers must be allowed to deviate from the written procedure depending on the different scenarios they face in the field.

In a statement on Twitter Monday, she publicly apologized to the Gilliam family and offered age-appropriate therapy to the children involved in the incident. Her agency would examine new practices and training around high-risk stops, she added.

Yet Teriana Thomas, Gilliam’s 14-year-old niece and one of the girls who had been pinned down, said there was little the police could do to regain her trust.

“It’s like they don’t care,” she told KUSA. “Who am I going to call when my life is in danger?”

Later on Monday night, as the video of the officers pinning the girls spread far and wide across social media, Aurora’s city council voted to make Wilson the city’s permanent police chief.