The arrests took place on Deal Road at about 8:39 p.m., police said.
Ocean Township Officer Dean Schoch performed a motor vehicle stop near State Highway 18.
An investigation by Schoch and other officers found that inside the vehicle was a loaded .22 caliber handgun and a bottle containing an alcoholic beverage. Prescription medications on two of the car's passengers included Xanax and Adderal.
All four of the car's occupants were charged with various firearm-related offenses and possession of alcoholic beverages while under the legal age.
Charged were the car's driver, Hannah Miller, 18, of Ocean Township; and her three passengers, Antonio Badillo, 20; Jasher Pena, 20; and Kavan Costello, 18, all of Ocean Township.
Badillo and Costello were additionally charged with possession of controlled dangerous substances.
All four suspects were taken to Monmouth County Correctional Institution pending a future court appearance.
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