A California deputy is under investigation, and has been reassigned outside the police department, after a disturbing viral video showed him punching and choking a teenage boy during an arrest, authorities said.

The Rancho Cordova Police Department and the Sacramento County Sheriff’s Office announced an “investigation into the use of force by our deputy” after a video of the April 27 incident posted on Twitter on Tuesday received more than two million views and was shared by former Democratic presidential candidates Julian Castro and Sen. Kamala Harris (D-CA).

“This is a horrific abuse of power,” Harris tweeted. “This officer must be held accountable.”

While authorities have not identified the Rancho Cordova police officer, family members said the boy in the video is 14-year-old Elijah Tufuno. The footage was originally posted by Tufuno’s older sister, who told NBC News the teenager was detained for holding a cigar.

“This is my 14-year-old nephew Elijah being restrained by this Rancho Cordova cop who felt the need to manhandle him,” his uncle, Justin Tufuno, wrote on Facebook, noting the teenager has a “chronic heart condition that prevents him from doing strenuous activity.” “My blood is boiling. Why did this man feel the need to shove his face in the dirt and throw punches after obviously restraining him with all his weight!”

In a YouTube video uploaded on Wednesday night, Rancho Cordova Chief of Police Kate Adams, who started the job on Monday, said the officer involved has been temporarily reassigned to a role outside the police department.

“I have viewed the video... and as a chief of police and a mom I have many of the same concerns that have been expressed,” she said.

She said the boy had expressed remorse in news reports about the way he handled himself, and a meeting between him and the officer has been proposed.

“It was heartening that on both sides, with the young man and the officer, there is a desire to listen to each other and understand how the situation could have been different,” she said.

Sacramento County Sheriff’s Office spokeswoman Sgt. Tess Deterding said in a statement that the incident began on April 27 while the Rancho Cordova deputy was “proactively patrolling” the area after receiving “complaints from citizens about hand-to-hand sales of alcohol, tobacco, and drugs to minors.”

“It’s important to put video footage into context, especially in relation to a use of force incident,” Deterding said. “In this case, the deputy saw what he believed to be a hand-to-hand exchange between an adult and [a] juvenile.”

But the deputy lost sight of the adult involved in the alleged exchange, and he instead approached Tufuno. Authorities say the teenager was “uncooperative and refused to give the deputy basic identifying information”—telling the officer he was 18-years-old.

The deputy had a “reasonable suspicion that criminal activity was occurring,” and attempted to detain the teenager so he could continue his investigation, Deterding said. Her statement claims Tufuno became “physically resistive,” causing the deputy to lose control of his handcuffs, forcing him to hold down the teenager while he waited for back up.

The video, however, shows a more violent altercation. Although the footage doesn’t show the entire incident, the deputy can be seen holding Tufuno down on the ground by the neck before punching him several times as he calls for back up. When the teenager tries to turn on his side, the deputy pushes his neck down again and turns him onto his stomach. Tufuno and a friend who filmed the altercation can be heard pleading with the officer to stop.

In an interview with Fox40, the 14-year-old said that while he had originally “lied” and “didn’t cooperate” with the deputy who had caught him buying tobacco, it did not give him the right to react so violently. He added that the confrontation occurred after he had handed over the tobacco product.

“He’s on top of me and it looks like he’s about to hit me. Like, I’m reacting like any other normal human being would,” Tufono said to Fox40. “It could’ve been better on both of our parts in this situation.”

“I mean, I do forgive him. I have nothing against the cop. He was just doing his job, I guess,” Tufono added. “And I just hope that we could meet again and be on better terms.”

Yralina Tufono, his 20-year-old sister, also posted several separate clips from the incident on Facebook, insisting her brother was not resisting arrest, but “was simply trying to get his arms free because he was in pain.”

The videos, which were eventually posted on Twitter, were met with immediate backlash from political leaders, civil rights leaders, and the general public. The Black Lives Matter chapter in Sacramento wrote on Facebook Tuesday evening there is “not one reason that validates a full-size armed man, to sit on, punch, and try and break the arms of a child.”

The group plans to hold a press conference about the incident on Wednesday afternoon.

Julian Castro, the former mayor of San Antonio and President Obama’s secretary of Housing and Urban Development, also spoke out against the attack, calling it “sickening” in a Twitter post.

“How many of these videos must we see before we do something about police violence in this country?” Castro wrote.