WAUSAU, WI (WTAQ) - Authorities in Wausau said a man had suspicions about his babysitter – so he secretly videotaped her, and the evidence is now part of a child abuse case against her.

19-year-old Jennifer Cronin of Rothschild is charged in Marathon County with felony reckless child abuse.

According to prosecutors, the father installed a camera because he thought Cronin was not watching his children carefully enough, after a 2-year-old boy fell down some stairs.

Officials said the parents reviewed the videotape and then called police.

A criminal complaint said Cronin repeatedly struck a 4-month-old boy in the face and head, and grabbed the baby’s wrist and yanked him from a floor into the air.

Cronin’s attorney says the allegations are out of character for her. She’s free on a signature bond, and is due back in court April 9th for a pre-trial proceeding.

A preliminary hearing is set for April 25th.