According to a report by the Jacksonville Sheriff's Office, a social worker at the school said the child was "destroying school property" and "attacking staff."
Nadia's mom Martina Falk said she was only told over the phone after police had been called.
She said her daughter was heavily sedated and held for a mandatory 48-hour period, in seclusion.
"I got a call saying that she is so uncontrollable that they had to Baker Act her," Falk told WTKR. "They called me and said 'Ms. Falk we're calling to let you know that there's nothing else we could do.'"
"There's nothing else you could do for my 6-year-old? When she was taken to that hospital to be locked away in this isolation, seclusion room. They said they did that as an attempt to calm her down."
Falk said she chose the school for her daughter last year, because Nadia has special needs, and had been told staff had been specifically trained to handle children with those conditions.
The video shows a calm Nadia being led from the school by a female police officer, who asks her: "You gonna be good? You're not gonna throw nothing around like you did in there, are you?" When the child agrees, the officer tells her: "Good deal, I appreciate it Miss Nadia."
As they approach the car, the child asks: "I'm going to jail?"
"No you are not going to jail, you are not going to jail," the officer replies. "You are not a bad person."
But after the officer locks her in the back of the cruiser, the body-camera records a conversation between her and a second officer, where they question the school's actions.
"I think they may have agitated her a little bit," she tells the second officer. "I don't see it how they say it... she's been actually very pleasant."
"I think it's more them just not wanting to deal with it," he replies.
"I think they're pushing the button," she says. "She's been so cooperative with me; talking, sat down, did everything."
"Yeah you poke the bear one too many times it's gonna scratch you," he replies.
"Yeah, 'cause they say this is the fourth out of five days she's been acting like this... well then I think it might be y'all," she goes on.
The male officer says: "I mean, a long time ago you got your ass beat and you knew not to..." but the female officer cuts him off: "She is fine, there's nothing wrong with her."
Inside the car, Nadia asks heartbreakingly oblivious questions, like "will we go to the house?", "it's a field trip?" or why the windows won't roll down.
Nadia was diagnosed with ADHD three years ago and takes medication for her mental health issues; she is awaiting test results to see if she is on the autism spectrum.
"She had a tantrum. 6-year-olds have tantrums. 6-year-olds with special needs have tantrums. The school knew about her tantrums," Falk's attorney, Reganel Reeves told News4Jax. "The police officer had no independent basis to take this child for Baker Act."
"If you can't deal with a 50-pound child, 6-year-old, then you shouldn't be in education."
Nadia's mom said the child has been traumatized by the incident, and she has since removed her from the school.
"I want answers," she said. "An apology would be nice, but it isn't going to fix the pain that I feel watching that video knowing that my daughter may have been provoked because their staff were irritated or maybe had a bad day and didn't want to deal with a special needs child. It's hurtful."
In a statement, the school district said: "With regard to the statements made on the video, note that the officers in the video were not present during the events which motivated the school to call Child Guidance, our crisis response care provider. The police officers were also not present when Child Guidance was intervening with the student. It was the mental health counselor from Child Guidance, not the police officer or school personnel, who made the Baker Act decision."
"Our procedure is to call Child Guidance when a student's crisis is not de-escalating and the student is at risk of self-harm or harming others. Our staff followed that procedure."
"As we stated previously, the student was calm when she left the school, but at that point, Child Guidance had already made the decision to Baker Act based on their intervention with the student."