Olney Juvenile Law Lawyer, Maryland

An affirmative defense to a crime. Self-defense is the use of reasonable force to protect oneself from an aggressor. Self-defense shields a person from criminal liability for the harm inflicted on the aggressor. For example, a robbery victim who takes the robber's weapon and uses it against the robber during a struggle won't be liable for assault and battery since he can show that his action was reasonably necessary to protect himself from imminent harm.

A lawyer who is elected to represent a state government in criminal cases in a designated county or judicial district. A D.A.'s duties typically include reviewing police arrest reports, deciding whether to bring criminal charges against arrested people and prosecuting criminal cases in court. The D.A. may also supervise other attorneys, called Deputy District Attorneys or Assistant District Attorneys. In some states a District Attorney may be called a Prosecuting Attorney, County Attorney or State's Attorney. In the federal system, the equivalent to the D.A. is a United States Attorney. The country has many U.S. Attorneys, each appointed by the President, who supervise regional offices staffed with prosecutors called Assistant United States Attorneys.

A quaint phrase that refers to the recording of an arrested person's name, age, address and reason for arrest when that person is brought to jail and placed behind bars. Nowadays, the book is likely to be a computer. Usually, a mug shot and fingerprints are taken, and the arrestee's clothing and personal effects are inventoried and stored.

Testimony or other evidence that fails to meet state or federal court rules governing the types of evidence that can be presented to a judge or jury. The main reason why evidence is ruled inadmissible is because it falls into a category deemed so unreliable that a court should not consider it as part of a deciding a case --for example, hearsay evidence, or an expert's opinion that is not based on facts generally accepted in the field. Evidence will also be declared inadmissible if it suffers from some other defect--for example, as compared to its value, it will take too long to present or risks enflaming the jury, as might be the case with graphic pictures of a homicide victim. In addition, in criminal cases, evidence that is gathered using illegal methods is commonly ruled inadmissible. Because the rules of evidence are so complicated (and because contesting lawyers waste so much time arguing over them) there is a strong trend towards using mediation or arbitration to resolve civil disputes. In mediation and arbitration, virtually all evidence can be considered. See evidence, admissible evidence.

A procedure in which the police place a suspect in a line with a group of other people and ask an eyewitness to the crime to identify the person he saw at the crime scene. The police are supposed to choose similar-looking people to appear with the suspect. If the suspect alone matches the physical description of the perpetrator, evidence of the identification can be attacked at trial. For example, if the robber is described as a Latino male, and the suspect, a Latino male, is placed in a lineup with ten white males, a witness' identification of him as the robber will be challenged by the defense attorney.

Latin for a 'guilty act.' The actus reus is the act which, in combination with a certain mental state, such as intent or recklessness, constitutes a crime. For example, the crime of theft requires physically taking something (the actus reus) coupled with the intent to permanently deprive the owner of the object (the mental state, or mens rea).

The defendant's formal answer to criminal charges. Typically defendants enter one of the following pleas: guilty, not guilty or nolo contendere. A plea is usually entered when charges are formally brought (at arraignment).

A situation in which the police detain a person in a manner that, to any reasonable person, makes it clear she is not free to leave. A person can be 'under arrest' even though the police have not announced it; nor are handcuffs or physical restraint necessary. Questioning an arrested person about her involvement in or knowledge of a crime must be preceded by the Miranda warnings if the police intend to use the answers against the person in a criminal case. If the arrested person chooses to remain silent, the questioning must stop.