PITTSBURGH -- A 22-year-old woman left her baby in a car with the engine running on Wednesday while she went to buy drugs on the North Side, police said.

According to court documents, Shannon Elizabeth Bozel left her 14-month-old son alone for 20 to 30 minutes while she purchased heroin for the father of her baby, who is under house arrest.

Police said when Bozel returned to her car, she drove away and struck another vehicle along Essen Street. The driver of the other car called 911.

Bozel was arrested in Northview Heights after police found three bags of heroin inside the vehicle.

Her son was placed in the custody of his grandmother.

Bozel was arraigned overnight on charges of possession of a controlled substance, endangering the welfare of a child and driving with a suspended license.

She is being held in the Allegheny County Jail on $25,000 bond. Her preliminary hearing is scheduled for next week.