ORLANDO, Fla. -- A martial arts instructor in Orlando was arrested this weekend on suspicion he inappropriately touching at least one of his young students.

Police said Stephen Gressett, 20, was arrested after a girl younger than 12 told officers that she was molested while taking part in a class at United Tiger Martial Arts located at 6700 Conroy Windermere Road in Orlando.

The alleged incident happened more than a year ago, police said. However, the girl recently came forward with the allegation.

The girl told police that Gressett singled her out at a time when all of the students were watching a movie. She said he pulled her aside and began to rub her private parts, according to the Local 6 report.

There were no adults around at the time of the alleged incident and the girl said other students were focused on the movie, she told police.

Gressett denies the allegation.

He refused to take a polygraph examination, according to legal documentation.

Gressett's sister said her brother has done nothing wrong.

"I just dropped him off at work," Gressett's sister said. "When I found out, I was just like…I was scared for him because this is something that can ruin him and he didn't do it."

Gressett is facing one count of lewd or lascivious molestation of a child, Local 6 reported.

Investigators said they are interviewing other students in the martial arts class in connection with the allegation.

Watch Local 6 News for more on this story.