The Sarver man accused of molesting an underage gymnastics student at three training facilities in Butler and Allegheny counties exhibited an escalating pattern of unprofessional and troubling behavior, one of his former employers said Wednesday.

Keith R. Callen, 45, of 117 Sarver Road has been charged with sexual assault by a sports official, volunteer or employee of nonprofit or not-for-profit organization, aggravated indecent assault, unlawful contact with a minor, corruption of minors and indecent assault.

The charges were filed April 26 in an Allegheny County district court by state police from Butler. The charges come amid allegations by a student that Callen improperly touched her on numerous occasions and had sex with her twice. The student, identified in court documents as “Victim 1,” told investigators that Callen began coaching her when she was 12 years old at Jewart’s Gymnastics in Hampton Township, Allegheny County.

Elaine Jewart, the owner of Jewart’s Gymnastics, said Callen worked part-time as a gymnastics instructor there for two or three years. During that time Callen became increasingly disruptive and defiant, Jewart said, flouting gym rules and policies in ways that made the business’ owners, fellow coaches and staff members uncomfortable and concerned.

Jewart said Callen’s “contrary” behavior started small: he refused to abide by the gym’s dress code. But as his time with the program continued, Jewart said Callen began to flout other rules — exchanging electronic messages with students and “friending” them on social networking sites like Facebook, in direct violation of the gym’s social media policy. Callen also would badmouth other coaches to students, Jewart said — sometimes within the coaches’ earshot — and began a troubling pattern of telling kids that he cared about them more than other staff members, Jewart said.

She said the gym’s major concern at that point was how unpredictable Callen’s behavior was, and how it might be sowing discontent among the students by showing favoritism.

“He put us in a defensive posture,” Jewart said. “What was he doing; what was coming next and where was this going? No one had ever done this before.”

At one point, Jewart said, Callen invited a female student to drive a new truck he had bought — something that left Jewart “aghast” at the prospect of what might have happened had something gone wrong. It was unclear whether the student accepted Callen’s offer, and Jewart said she couldn’t be sure of when the offer was made.

She also said Callen exhibited an escalating pattern of physical contact with students. Massaging students’ sore feet turned into back massages, then hamstring stretching using techniques Jewart said the gym expressly prohibits.

“Touching like that in our program was not used,” she said. “Some programs do it; we didn’t.”

Jewart said the gym eventually began warning other coaches about Callen’s conduct. In March of 2012, after being confronted about his behavior, Callen left the gym, Jewart said.

He would continue coaching gymnastics at West Deer Township-based Trinity Gymnastics in Allegheny County.

In a written statement Wednesday Brian McGrath, the owner and operator of Trinity Gymnastics, said the business was contacted by state police in February regarding the allegations against Callen, and that the gym has “fully cooperated” with the investigation. McGrath said Callen was in good standing with the U.S. Gymnastics Association when Trinity hired him, and there were no apparent concerns about his conduct as a coach.

“If there were any issues or complaints filed with the appropriate government authorities and USGA did not give their approval, Trinity Gymnastics would have never hired Keith Callen,” McGrath said.

Trinity and Callen “mutually ended his employment” in August 2013 after Callen was discovered giving a student a private lesson one Sunday when the gymnasium was closed — something McGrath said is “strictly prohibited” by USGA rules without another staff member or instructor present.

“Since this did not appear to be a suspicion of child abuse and at the time no mechanism was in place to report the violation of USGA rules, nothing further was done,” McGrath said.

A message left at the Elite Athletic Center in Butler Township, the third gym where Callen allegedly molested the student, requesting comment was not returned.