Authorities arrested 33-year-old activist Adam Hollingsworth — also known as the "Dreadhead Cowboy" or "Census Cowboy" — after a Monday protest in which he rode a horse on a Chicago highway until the bleeding horse collapsed.

The horse, which is in critical condition due to its injuries, may now need to be euthanized.

Chicago Mayor Lori Lightfoot (D) tapped Hollingsworth to work with her earlier this year to boost census participation in the city.

What are the details?

According to a report from WTTW-TV, Hollingsworth rode the horse for more than seven miles on the Dan Ryan Expressway during Monday's impromptu protest.

The horse, which was reportedly not outfitted with proper shoes for concrete, collapsed after running for about an hour.

Cook County prosecutors said the horse's treatment was the "equivalent of forcing an 80-year-old woman run a marathon," WTTW reported.

Cook County Assistant State's Attorney Kevin Deboni said that the horse was nearly run to death and suffered "extensive damage" to its health.

Deboni said that the horse's eyes "were dilated to the point they looked like cartoon eyes."

All for #KidsLivesMatter

Hollingsworth said that he rode the horse on the Dan Ryan Expressway during rush hour to support the #KidsLivesMatter movement, according to the outlet, which describes the initiative as one "that aims to raise awareness and motivate residents to fill out the census to help communities receive better funding."

According to Block Club Chicago, the movement is in response to children killed by gun violence.

In August, Hollingsworth told the Block Club, "When you get kids occupied and they've got things to do with their time and their life … all this senseless killing that's going on, it'll slow down a whole lot. It's important to support dance groups [or] anything that's got something to do with kids. If it's something positive, support it."

Witnesses of the Dan Ryan Expressway incident told the outlet that they saw Hollingsworth kicking and whipping the horse to keep it running even after it slowed its pace due to exhaustion and injury. Shortly after, the horse collapsed on the ground.

Emergency veterinarians responded to the scene and took the horse in for treatment of severe dehydration, overheating, and lacerations to its front legs that caused heavy bleeding. Authorities took Hollingsworth into custody.

WFLD-TV reported that the horse also had sores beneath its saddle, which was not properly padded.

A felony charge and a rebuke from the mayor

In a statement, Mayor Lightfoot's office condemned Hollingsworth's "stunt."

"There is a right way and a wrong way to call attention to issues of great importance and this stunt was decidedly the very wrong way," the mayor's office said in its statement.

Hollingsworth was charged with a felony count of aggravated cruelty to an animal, as well as misdemeanor counts of reckless conduct, trespassing, and other traffic-related offenses.

At the time of this reporting, the horse remains in critical condition, and will never be able to be ridden again.

The horse may also have to be euthanized due to its injuries and "due to the suffering the animal will likely endure for the rest of its life."

Hollingsworth was held on $25,000 bond during a Wednesday court appearance, and was required to pay 10%. He is due back in court on Sept. 30.

'Lori, come help me, I can't do it alone'

On Thursday, a tearful Hollingsworth told the Chicago Sun-Times that he did not abuse the horse.

"My focus is on the 'Kids Lives Matter' because if you look up the history of when it comes down to kids getting killed, 2020 is the highest rate ... and it ain't right," he told reporters. "Everybody is trying to steer away from that part, and that is very important — that is an important topic we need to stick on."

Hollingsworth insisted that how he treated the horse was "no different than how horses are treated in the circus or at a racetrack," the outlet reported.

"The people that don't know anything about horses looking from the outside in, you would think that what I did was cruelty to animals," he explained. "But if you go to a racetrack, it's 100 times worse, if you go to a circus, worse. ... It's way worse than what I do to my horses. I probably could've did a little bit less, but I had to make a statement."

He also insisted that the description of the horse's injuries were exaggerated, and that he would like to appoint an independent veterinarian to examine the horse.

"I think that is just a way to make the situation seem worse than it is because I am a black brother and I am doing very good for the community and standing up for the Kids Lives Matter movement and not focused on anything else," Hollingsworth reasoned.

He also revealed that he has been the subject of abuse since his arrest.

"Every day I step outside I am taking a chance with my life," he said. "I basically look at [the hate mail] and just close them. I can't change how a person feels."

He also called upon Lightfoot to defend him.

"When [Mayor Lightfoot] called upon me [to assist with the 2020 census], I was there for her," he added. "Monday was my stress signal: Lori, come help me, I can't do it alone."