A use-of-force investigation is underway after an 18-year-old woman was pulled off a Metro train and arrested Monday afternoon by an LAPD officer who she said confronted her for having her foot on a train seat.

The incident was captured on a cellphone video that was shared to Facebook, earning nearly 1 million views by midday Tuesday. Brock Bryan, who recorded the 10 1/2-minute video, can be heard objecting to the teen’s treatment by the officer, alongside other witnesses.

One of those witnesses was also arrested after allegedly spitting at an officer.

Bethany Renee Nava of North Hollywood was riding the train when police say she was being loud and boisterous, prompting her to be removed and arrested, Los Angeles Police Department Officer Mike Lopez said.

In the video, Nava and other witnesses repeatedly say that the girl had only had her foot on a seat in the train when the officer confronted her. Bryan said the teen was on a Red Line train when the arrest took place at the Westlake/MacArthur Park station about 3 p.m. Monday.

In the video, the officer – who wears a sergeant’s stripes on his uniform sleeve – motions to Nava to get out of her seat. He says, “I already told you what to do and you didn’t. You disobeyed me. You’re getting off the train.”

The sergeant takes Nava by the arm and begins to pull her out of the seat.

“I paid to be on this train. Stop,” Nava can be heard saying, using an expletive at the sergeant.

She grabs onto a pole and tries to remain inside the train, pulling back toward her seat so she can get her belongings. But the sergeant pulls her off the train and pushes her up against a wall on the platform, putting her hands behind her back.

As Nava looks down, gasping and appearing terrified, the sergeant calls for backup on his radio. Bryan, who follows the pair onto the platform, can be heard asking the sergeant not to arrest Nava.

“Over her foot on the train? That’s so ridiculous. That’s really abuse of power, officer,” Bryan says. “She wasn’t blocking anybody else from sitting down.”

The sergeant releases Nava and she continues to argue with him. At one point, after she gives the officer her name, a bystander tells her not to give her name. Then the sergeant turns to that bystander and says, “You’re next, buddy. You don’t get to tell me what to do.”

A second woman, later identified by LAPD as 22-year-old Selina Lechuga, can be heard shouting expletives at the sergeant as a small group gathers.

“You’re going to take her to jail for putting her foot on the bus? Are you f—ing kidding me? You really have nothing to do,” Lechuga says.

Nava, who can also be heard cursing, questions why she was pulled off the train for putting her foot on the seat; the sergeant explains it is one of the rules of the train.

A few minutes later, another train arrives and several more officers get off. The sergeant directs one of the officers to take Nava into custody, and that officer handcuffs her. Then two other officers cuff Lechuga’s hands behind her back as she protests.

“This is racism,” Lechuga says. “This is what we are: 2018, motherf—ers like this want to just try to act like they can do whatever they want. F— you guys.”

Lechuga then appears to spit at one of the officers – possibly the original sergeant – as she is being taken away.

More than a half-dozen officers responded to the platform, the video shows.

Nava was arrested on suspicion of being loud and boisterous on a train, Lopez said. She was released but is due in court Feb. 15.

Lechuga was arrested on suspicion of battery on a police officer for spitting and her bail was set at $20,000, Lopez said.

Los Angeles County inmate records do not show booking information for anyone by the name of Bethany Renee Nava or Selina Lechuga.

Lopez confirmed LAPD is conducting a use-of-force investigation for Nava’s arrest.

Nava’s mother told KTLA the high school senior was taken to a hospital with a sprained wrist and some contusions following the incident. She stressed that her daughter had her heel on the edge of her own seat on the train.

The family is getting an attorney, she said.

Metro’s customer code of conduct states that “placing feet or shoes on seats or furnishings” is prohibited disorderly conduct, which may be penalized with a warning and/or ejection from the train.

Deputy Chief Bob Green told the Los Angeles Times police began investigating the use of force after receiving a complaint about the incident. Police have been doing “a lot of code-of-conduct work on the Metro trains, and it has a lot of public support from riders,” Green told the newspaper.

LAPD took over policing of transit facilities within the city of Los Angeles from the Los Angeles County Sheriff’s Department last summer.

Warning: The video embedded below contains graphic language.