A spooked Dallas police horse injured a teenager at the State Fair of Texas this week.

Ian Macharia, 17, was taken to hospital after the horse hit him near Big Tex.

His mother, Esther Macharia, says her family attends the fair every year.

Their first stop on Tuesday afternoon was a car show for Ian, then they went to Big Tex.

As she and Ian waited their turn in front of the State Fair symbol, Macharia heard a loud noise behind her as Ian stood directly over her right shoulder.

“I could hear a crash behind me so I turned around and saw a big police horse running and there was a police officer on it but he fell down. Then I looked down and my son was right there,” Macharia recalls.

Ian's father's video shows first responders lifting Ian onto a stretcher.

He had a seizure, says Macharia, and then passed out.

“I was withdrawn at that point because the thought that he had died was so scary,” Macharia said, holding back tears.

Ian spent several hours at Baylor Medical Center in Dallas and was released later that night, says the family's attorney, Ramez Shamieh.

“We want to get more answers, we want to find out why this happened, we want to bring justice to this family and we want to make sure something like this doesn’t happen again,” Shamieh said.

Shamieh says social media has provided some clues as to what may have spooked the horse and hopes more videos come to light.

Asked if he believes mounted patrol horses are appropriate for crowds at the State Fair, Shamieh replied, “I think it's all for show and in this particular scenario I think it was overkill.”

Dallas police said Tuesday the horse was spooked while patrolling Big Tex Circle.

As the officer attempted to regain control of the horse, a fairgoer was reportedly injured and the officer was thrown back.

The officer was checked for injuries.

The horse returned to the stables, police said in a statement.

Macharia says her son is recovering at home from a head injury and was unable to return for his senior year at Princeton High School.

“He started saying he was having nightmares about it,” Macharia said.

She says Ian doesn't remember what happened, but says for her, it's a memory that won't go away.

“I can’t even get away from it. I'm thinking about it. “I replay it in my head and think, how?” Macharia said.

It's unclear what spooked the horse and whether it returned to patrol. On Thursday, Dallas PD did not provide any further information about the incident when contacted by NBC 5.