A Delaware County gym teacher was arrested Tuesday and charged with sexually assaulting a 15-year-old female student in his office, officials said.

William Barber, 38, of Glen Mills, taught physical education and health at Garnet Valley Middle School, where he also coached football and baseball.

He was placed on administrative Monday evening, the school district wrote in a letter to parents Tuesday. The letter also described Barber as a popular teacher and the father of a 4-year-old daughter with cancer.

Barber appeared on 6ABC last week to speak about a fundraiser for his daughter, and the school district superintendent said the school community has participated in a number of fundraisers for the family.

Police said Barber was the 15-year-old victim's former gym teacher.

The two began sending text messages and private Twitter messages, she told police, and she sent him nude photographs. Barber and the girl kissed in Barber's office during the first week of school this year, an arrest affidavit stated, and had sex with her in his office on Sept. 12 after a football practice.

Garnet Valley School District Superintendent Marc Bertrando said Barber had passed all child-abuse and criminal history clearances when he was hired in 2002.

The incident came to light when students at the high school informed staff on Monday about rumors of an innapropriate relationship between Barber and a student, the superintendent wrote in his letter to parents.

Barber was arraigned Tuesday and was held in Delaware County Prison in lieu of $250,000 bail. His attorney could not be reached for comment Tuesday evening.

The school district planned to hold meetings with middle school and high school students Wednesday morning to discuss the situation.

"As we meet with students in the coming days and weeks, we hope to help them work through their concerns and reassure them that while this very popular, well-liked teacher certainly betrayed the community's trust," Bertrando wrote, "there are many adults in their lives who can be trusted and relied upon."

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