Called "civil asset forfeiture," the police are under no obligation to give the property back to you. Instead, police departments will steal your stuff, hold it in storage (accruing fees in most cases), and then sell your stuff to the highest bidder.
Police have no qualms about stealing your property, especially after you've been arrested for a crime. Even though every citizen is supposedly innocent until proven guilty, police will routinely confiscate, cash, guns, and real property from those who've been charged with a crime, even property from other members of a family living under the same roof. After all, it is difficult to prove ownership without a receipt. More sinister, however, is the fact that you need not even be accused of a crime for police to steal your stuff.
The most egregious case of civil asset forfeiture of which we are aware comes from Oklahoma. To keep society safe, sheriff's deputies in Muskogee County, Oklahoma robbed a church and an orphanage of $53,000. Real American heroes.