A criminal lawyer deals with all areas of criminal law. A criminal lawyer helps defend the persons accused of crimes in state or federal courts. A criminal lawyer also deals with the three most consistent items that make up a crime: an act, a mental state, and the intent to do social harm. The types of crimes that criminal attorneys deal with are classified as misdemeanors, ,which are less serious, and felonies, which can be severe depending on the crime committed. A criminal lawyer is needed when the complainant makes an accusation that is investigated by the police.