Seems that the city of St. Louis, like many cities, allows the police to confiscate the cars of people suspected (but not necessarily convicted) of certain crimes. They have a contract with a city towing firm, and said firm was allowing police officers and their families to "rent" confiscated cars free of charge, sometimes for months on end. Officers and their families could also sometimes purchase the confiscated cars at a fraction of the cars' value.
At the same time that this kind of thing is going on this city gets rated one of the most dangerous in the US.