If someone is taken into custody for alleged criminal activity, they are required to appear in court for legal proceedings related to the criminal trial. Sometimes the nature of the crime or the nature of the defendant (if it is possible that he is a runaway risk) will behoove the court to require that the defendant be jailed. With this the court will usually set a bail amount which if paid will act as surety for the appearance of the defendant in the court as required. If the defendant fails to show up as demanded by the court, he will forfeit the bail money or property, and may even incur further fines and imprisonment.
Often the amount of the bail set is high, especially in violent criminal cases, which requires the involvement of a bail bonds company. The company will act as surety on behalf of the defendant (for a fee), and put up the required money to bail the defendant out.
Four states, Illinois, Kentucky, Oregon and Wisconsin, have entirely outlawed the role of bail bondsmen, and have instead put in place the use of the 10% cash deposit alternative where the defendant can pay the court 10% of the bail amount in cash, in lieu of putting up security for the full amount of the bail.
The bail money is returned to the defendant regardless of the outcome of the trial, if he appears before the court as required.