That vehicle, from Cardinal Health, was found in the 1900 block of Ithan Street in Philadelphia.
The white car was used to transport radioactive medical waste held in containers. The driver had at least three pick-ups on Friday.
In the early hours of the investigation, the Department of Homeland Security was notified because of the nature of the material in the car.
However, officials later said the material was not hazardous.
Officers say the vehicle was found Saturday morning parallel parked and the containers were still inside.
An armed suspect with an accomplice driving a black Pontiac Bonneville held the driver at gunpoint Friday afternoon in the 200 block of Mill Street in Darby, carjacking his company-issued 2013 white Toyota Matrix.
Police are still seeking the suspects in this case.