A former police officer in Montgomery County has been charged with shooting a teenage girl after a road-rage incident, prosecutors said Thursday.

Owen W. Farmer 3rd, 45, of the 1900 block of Second Street in Upper Gwynedd Township, allegedly fired three shots Saturday night into the rear of a BMW sport-utility vehicle, wounding the driver's 15-year-old daughter who was sitting in the front passenger seat.

Farmer, who was a police officer in Upper Gwynedd, was charged Tuesday with two counts of aggravated assault and related offenses. He was released after posting $50,000 bail.

Farmer was not in either of the vehicles when the altercation began, police said.

Police said that Amber Shank, Farmer's 20-year-old step-daughter, was driving a Ford Escape in Montgomeryville and approached a BMW X5 driving slowly and appearing to turn when it merged back into the roadway.

After Shank passed the BMW, its driver, Elma Campos, started honking the horn and flashing the lights, police said. Shank flashed her middle finger at Campos. Campos began following Shank.

Shank called Farmer and said she was being followed and that he needed to come outside with his gun, police said.

When Shank arrived at Farmer's driveway, he ran into the street to confront the occupants of the BMW. Campos told police she saw Farmer's handgun, a .40 cal. Glock, and tried to drive away, police said.

As she was backing the BMW away, it ran over Farmer's foot. He then fired three shots into the vehicle as it sped away. One of the bullets struck Campos' daughter in the back.

Campos drove her daughter to Einstein Medical Center Montgomery in East Norriton. She was treated and released. Police recovered three bullets from the BMW.

Farmer suffered a broken foot and was taken by ambulance to Abington-Lansdale Hospital to be treated.