A teleological system of ethics states that the consequences of an action are a direct reflection of the goodness or badness of that action.
A deontological system of ethics states that the goodness or badness of an action is a reflection of whether that action conforms to some preestablished rule.
Therefore, the focus of the first system is on the result of action and the focus of the second system is the action itself.
Ethical practices in the criminal justice system depend on what component of the justice system we are looking at. Judges and others who act in court to decide the fate of a lawbreaker more often use a teleological system than a deonotological one (to a certain extent as laws must be conformed to). Whereas, in the field an actual police officer is expected to follow a deontological system of ethics by enforcing pre-established law.