Kenneth J. Mowerson III, 54, was being held on $300,000 bail in the Bergen County Jail, charged with aggravated sexual assault, sexual assault, child endangerment and witness tampering.
The girl on Tuesday went to Hawthorne police, who determined the alleged assaults occurred in Mahwah, Acting Bergen County Prosecutor Gurbir S. Grewal said Friday.
An investigation by detectives from Grewal's Special Victims Unit and Mahwah police followed, assisted by Hawthorne police.
They couldn't find Mowerson at first, the prosecutor said.
Then, just after 5 p.m. Thursday, the off-duty officer spotted him, Grewal said.
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