Theodore Wilson, 52 -- who knew the girls' family -- began sexually assaulted the girl at her Jersey City house last year, Hudson County Prosecutor Esther Suarez said.
The incidents were first reported to the Jersey City Police Department, which notified the Hudson County prosecutor's Special Victims Unit.
Wilson was arrested Thursday at 11:15 p.m., at the prosecutor's office without incident, authorities said.
He was charged sex assault by contact, child endangerment and lewdness.
A court hearing was scheduled for Wednesday, Oct. 9.
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