CRETE, Ill. (CBS) — A man whose job was to counsel troubled children, and who also worked as a high school sports coach, now stands charged with trying to arrange a sexual tryst with a 13-year-old girl.

And Newsradio 780’s Steve Miller reports that investigators fear he might have had inappropriate contact with as many as ten other girls.

John K. Martynus, 39, of Plainfield, was arrested on Monday at a fast food restaurant in Crete – the place where he allegedly had arranged by text message to meet a 13-year-old girl.

Police said he was actually texting with two male undercover officers.

LISTEN: Newsradio 780’s Steve Miller Reports

“The exchange that was in the chat logs and the conversation that he was having – what he thought he was having with a 13-year-old female – were so explicit and so aggressive,” Crete Police Chief James Paoletti said. “And when we found out what he did for a living through the chat logs, we were really concerned for the safety of others, so we thought it would be best and prudent to make a move right away and take him into custody.”

Martynus works for Will County as a youth mental health counselor and is also an Illinois High School Association coach and referee, according to Paoletti.

“Both in his hobby and professional life, he has exposure to young children who are very impressionable, very vulnerable,” Paoletti said.

When he was arrested, Martynus had just finished refereeing a basketball game in Beecher and was insistent on meeting the girl Monday evening.

“I can tell you that the investigation is continuing and that there is some perception that there may be some victims out there,” said Paoletti.

When Paoletti was pressed for a number, he replied, “As many as ten.”

A Will County State’s Attorney’s office spokesman said Martynus is being held on probable cause and is expected to be formally charged on Wednesday with indecent solicitation of a child.

Martynus was in custody Tuesday evening and was expected to be in Will County bond court Wednesday to face charges of indecent solicitation of a child, traveling to meet a minor and using an Internet device to lure a child for sexual purposes.

Police said Martynus is married. Calls to his home were not answered.

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