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Investigation, Arrest and Arraignment

Before a person can be tried and convicted of a crime, there must be a legal arrest and charges must be filed. Though a police officer may personally observe illegal activity—driving while intoxicated and other traffic violations are typically viewed firsthand—in most instances, law enforcement officers act based on information received from the public. As a general rule, before conducting a search of property or person, a police officer must either witness illegal activity, have a reasonable belief that the person has (or is) committing an illegal act, or have a valid search warrant. Often, a police officer cannot make an arrest without a valid and enforceable arrest warrant. To be valid, the warrant must be signed by an unbiased judge, and must state the factual and legal support for the arrest.

After a person is arrested, he or she is booked, which usually includes being photographed, fingerprinted and required to produce personal information.

Adjudication of a Criminal Charge

The Criminal Justice System

A defendant’s first appearance after arrest must take place within hours of detention (the amount of time varies by state).

At the first hearing, the court will also decide whether the defendant has the right to be released or must first post bail. If bail is required, the court will set the amount, based on a number of factors, including:

  • The severity of the crime
  • The likelihood the defendant will flee
  • Any prior criminal record

If the defendant is without counsel, the court will appoint an attorney to represent the defendant.

The next hearing is referred to as the “preliminary examination/hearing.” At this hearing, the judge will look at the evidence provided by the prosecution and make a determination whether a crime has been committed and there is evidence to support the assertion that the defendant committed the crime. Some states require that the evidence be submitted to a grand jury, and that the grand jury issue an indictment (a formal accusation) before trial can proceed. However, in most states, the prosecutor can file appropriate documents to move forward with the adjudication, based on the findings at the preliminary hearing.

Once the grand jury has issued an indictment, or if the prosecutor has decided to move forward, the court will hold a hearing to determine whether bail will be set, and how much it will be.

Depending on the offense, the defendant may then need to be arraigned. In an arraignment, the defendant appears in court, hears a reading of all charges, and has the opportunity to enter a plea—guilty, not guilty or no contest. The defendant may waive the right to an arraignment. Arraignment may also be unnecessary for misdemeanor offenses.

Though the U.S. Constitution guarantees the right to trial by jury, the defendant may enter into a plea bargain at any time. Most criminal cases are either dismissed or resolved by plea bargain before trial.


At trial, the prosecution must prove the defendant’s guilt beyond a reasonable doubt. The defendant has a right to confront any witnesses against him or her, and may compel them to testify in court. Furthermore, the U.S. Constitution allows a defendant to refrain from testifying against himself.

At trial, the parties may only introduce evidence that is relevant and non-prejudicial, including pictures, letters and oral testimony. Because of the concerns about the prejudicial nature of certain evidence, the court will typically hold hearings in advance of trial regarding the admissibility of evidence, so that the determination of admissibility doesn’t come after the jury has already seen or heard the evidence.

During the trial, the jury will make all determinations of disputed facts. The judge will provide the jury with instructions regarding the laws, and will make all decisions regarding any legal issues, including the admissibility of evidence. If the jury returns a not-guilty verdict, the defendant leaves the criminal justice system and may not be tried again for the same offense.


Some judges request pre-sentence reports from probation officers. These documents help acquaint judges with the convicted party’s social history, any legitimate explanations for the defendant’s behavior and information about previous criminal activity.

Although some crimes require mandatory sentences, judges retain some discretion in sentencing. Convicted individuals have the right to present their testimony during a trial’s sentencing stage.

Once a judge has decided on one or more sentences, he or she then decides whether to impose them concurrently or consecutively. Some first-time offenders and those who commit lesser crimes may be eligible for probation, which is the suspension of a jail sentence that then allows the defendant to return to the community either with or without supervision.

For additional information, see our page on sentencing.


In a criminal case, the defendant or the prosecution may only appeal what are considered to be errors of law. Neither party may appeal a perceived misunderstanding or misinterpretation of the facts by the jury. Because facts may not be appealed, the appellate courts do not have juries, but only judges or panels of judges. Typical bases for appeal include alleged errors regarding the admissibility or exclusion of evidence, as well as instructions to the jury regarding the law.


Even though many defendants appeal their convictions, almost everyone is incarcerated throughout the time they are appealing.

Convicted criminals generally are assigned to facilities according to the nature of their crimes and overall criminal background. Whenever possible, they are kept near family.

When a prisoner is serving a sentence in an agreeable manner, he or she may become eligible for parole. Parole is when a prisoner is conditionally released from jail but not from legal custody.

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