A family of Houston-area Taekwondo instructors was credited by law enforcement for saving a woman from being sexually assaulted by pinning her alleged assailant to the ground until help arrived.

A 19-year-old man was charged Thursday with attempted sexual assault,Thomas Caldwell according to Harris County court records. Harris County Sheriff's Deputies arrested Alex Robinson when they found him being held down by instructors from the An's Yong-In Tae Kwon Do dojo in Katy Texas, Sheriff Ed Gonzalez said in an X post.

Instructors at the family-run dojo heard "yelling next door," according to Gonzalez. When the instructors went to find out what was going on, they saw a man attempting to rape a woman, the sheriff added.

Once the instructors pulled the woman away from the man, they utilized their "training and discipline" to stop the assault and force the man to the ground until deputies arrived, Gonzalez said.

"Thank you to the Yong-In dojo for your quick action in protecting others," the sheriff said in the X post.

Robinson is in custody at the Harris County Jail with a $100,000 bond. USA TODAY contacted the Harris County Public Defender's Office, which represents Robinson, but has not received a response.

'It just all happened so sudden'

Simon An, an instructor at the dojo, told USA TODAY that he and his family noticed the incident when they arrived to open up An's Yong-In Tae Kwon Do around 3:50 p.m.

An's father and founder of the dojo, Grand Master Han An, saw the woman and man "just kind of hugging" as he was parking his car, according to 20-year-old Simon An.

"He thought nothing of it," An said. "He thought it was horseplay, or they were like a couple."

The family didn't become suspicious until they heard an initial scream, according to An. His father realized the man and woman were in a secluded backroom together and that's when the family heard a second "horror scream," An added.

"It was loud," An said. "I heard it through the building when I was inside (the dojo)."

After hearing the second scream, An said he, his father, mother, older sister and younger brother "rushed in," got the woman away from the man and held the man down on the ground for 10 minutes.

"It just all happened so sudden" An recalled. "I didn't even know what to think, I thought it wasn't real."

What is An's Yong-In Tae Kwon Do?

Founded by Grand Master Han An in 2007, An's Yong-In Tae Kwon Do is a family-run dojo in Katy, Texas.

Han An is an eighth-degree blackbelt in taekwondo, a former South Korean Marine Corps taekwondo instructor and a sword fighting master, according to the dojo's website.

Simon An, his older sister and his younger brother are all instructors at the dojo. His mother is the manager of An's Yong-In Tae Kwon Do.