The Illinois Criminal Code permits the use of deadly force to prevent death or great bodily harm; to prevent the defeat of an arrest by resistance or escape where the arrestee is either committing a forcible felony, attempting to escape by the use of a deadly weapon, or otherwise indicating he/she will inflict great bodily harm unless arrested without delay. It is also permitted to prevent a forcible felony; to prevent a felony in a dwelling; to prevent an assault after a violent, riotous entry into a dwelling; or to prevent an escape from a penal institution. Despite repeated judicial refinement and interpretation of these provisions, several areas of legal uncertainty remain. For instance, off-duty police officers still cannot be sure whether it is illegal to carry a gun outside of their jurisdiction or whether they can shoot at a fleeing forcible felon whom they recognize. They cannot be sure to what extent they may be held liable for shooting at fleeing forcible felons. It is very important for police officers and their supervisors to have clear legal parameters of the use of deadly force when they are involved in civil cases related to this use. The plaintiff is aware of expanded legal theories with which to sue not only the officer involved, but also the officer's supervisors and municipality for failure to provide sophisticated firearms training. Even with statutory modification and legal refinement, however, the police officer will always have the capability to be 'judge, jury, and executioner' in critical decisionmaking situations regarding the use of deadly force. Complaints of abuse should be met with detailed departmental regulations about police use of weapons and improved officer training. Footnotes are provided. (Author abstract modified)