The girl met Wilfredo Hernandez, 48, at a church festival and exchanged phone numbers with him, authorities said. Later that night, he convinced the girl to meet him in the area of 14th Street. When she arrived, they entered a nearby building, where the assault took place, the prosecutor's office said.
The girl's mother called Union City police, who contacted the prosecutor's Special Victims Unit. Hernandez was arrested around 3 a.m. Monday.
In addition to sexual assault, he has been charged with luring and enticing a child, criminal sexual contact and endangering the welfare of a child.
He was being held at the Hudson County jail pending a court appearance Thursday.
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