A West Chester high school swim coach was arrested Wednesday on charges that he posed as a swimmer's father, plied her with beer, and had sex with her.

Kenneth William Fuller, 47, head coach of the Bayard Rustin High School swim team, was charged with felony sex assault and corruption of a minor.

"This was a despicable violation of trust," said Chester County District Attorney Tom Hogan.

A member of the team, a teenage girl, told police that Fuller took her to a Kennett Square hotel April 27 and gave her "multiple" beers, court documents state. They had sex twice at the hotel, the documents allege.

On May 2, officials at Rustin received a phone call from a man who identified himself as the girl's father, telling them the girl had a doctor's appointment at Children's Hospital of Philadelphia, according to court papers. After leaving school early, the girl met Fuller at the same Kennett Square hotel for sex, the papers state.

Before leaving, Fuller gave the girl a document that said she had been treated at Children's. The girl turned the document over to school officials, who excused her absence, West Goshen detectives said.

On May 4, the pair met in Thornbury Park, where Fuller offered the girl more beer and had sex with her on a park field, detectives said.

Detectives spoke Monday with the girl's father, who told them that his daughter was not a patient at Children's and that he had never called the high school to have her dismissed early from school.

Contact staff writer Sam Wood at 215-854-2796 or samwood@phillynews.com.