Deputies arrested Heather Koon after finding sexually explicit photos on a phone belonging to her boyfriend, a convicted sex offender, The (Elyria, Ohio) Chronicle Telegram reported Tuesday.
The boyfriend, James Osborne, denied taking the photos, which allegedly show Koon engaging in sexual acts with children, said Lorain County sheriff's deputies.
Elyria City Prosecutor Scott Strait requested the high bond, saying it was justified by the "horrendous nature of the crime." He said prosecutors have "very strong evidence" against the woman.
Koon was an employee of the ABC Katz day-care center, where the assaults allegedly occurred, from August 2012 until March 2013. She was working at a day center in Amherst when she was arrested Friday.
Carlos Johnson, an attorney for ABC Katz, said Koon passed an extensive background check before she was hired.
Osborne faces unrelated charges, including violation of probation.
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