BRIGHTON, Colo. -- Brighton police have arrested a teacher employed at Brighton Collegiate High School for investigation of sexual assault on a child by one in a position of trust.

Ralph Kelly, 34, of Denver, was arrested after midnight Thursday morning following an investigation into allegations he sexually assaulted a student of the school in early December.

Kelly teaches social studies and German at the school. The Irishman was hired last spring after a background check and started his job on Aug. 15, according to the attorney for the high school.

"His job performance was excellent," Attorney Barry Arrington said at the school's Board of Directors meeting Thursday night. "There was no indication of problems of any nature."

A handful of parents with children in Kelly's classes also attended the meeting.

"It's a good place to be, I'm not afraid of my daughter being here," said a parent supporting Kelly. "I had a parent-teacher conference with my daughter and I was totally satisfied with how he handled the conference," the parent said.

Another parent, who also asked not to be identified, expressed concern. She told reporters she's considering moving her son to another school. "To me as a resident and parent, it's embarrassing."

A student outside the board meeting told 7NEWS Kelly was friendly to everyone. The student said his only concern stemmed from a request he said Kelly made to him to participate in a study about gay high school students. The student declined.

So far investigators have not released the gender of the alleged victim, and have only said the incident occurred in early December.

Kelly posted $20,000 bond Thursday afternoon, however he remained in custody for a time at the request of Immmigration and Customs Enforcement, said Adams County Sheriff's Office spokeswoman Sgt. Candy Baker.

The charter school is the same one where Carrie McCandless was a teacher. McCandless was sentenced to 45 days in jail last summer for providing alcohol to, and having unlawful sexual contact with a 17-year old student. Her husband was the school's principal and the incident gain nationwide publicity.

The high school changed its name after the McCandless issue and after a new facility was built. The charter school is affiliated with the Brighton school district but is semi-autonomous.

A third, incident resulted in similar charges in December of 2005. A substitute teacher at the school was sentenced to 60 days in jail for sexual contact with a female student.

Anyone who has information relevant to the investigation was asked to contact Detective Lopez at the Brighton Police Department at 303-655-2335.