Richard Di Giovanni, 39, was found with the teen on Thursday at about 2 a.m. Police say the two were talking inside a car on Hubbard Street. The girl's grandmother's call to authorities led to the arrest.
Di Giovanni was booked on suspicion of contributing to the delinquency of a minor. The relationship between Di Giovanni and the girl remains unclear.
The deputy is now out on bail.
The Associated Press contributed to this report.
