Criminal procedure is the process related to the investigation, arrest, charging, and conviction or acquittal of a criminal defendant. Much of criminal procedure is comprised of processes and rules through which the government (state, federal, or municipal) enforces substantive criminal law and through which a criminal defendant’s Constitutional and other rights are protected.

The law of criminal procedure is primarily located in the applicable state or federal rules of criminal procedure and state and federal court opinions interpreting and applying Constitutional and other legal rights.

In Connecticut, criminal procedure is governed by a combination of state statutes, the Connecticut Practice Book (which outlines rules of procedure for the state's courts), and federal law, including Constitutional protections. These procedures dictate how law enforcement conducts investigations, arrests, and how charges are brought against individuals accused of crimes. The process ensures that a defendant's rights, such as the right to a fair trial, the right to counsel, and protection against self-incrimination and unreasonable searches and seizures, are upheld throughout the criminal justice process. The Fourth, Fifth, Sixth, and Fourteenth Amendments to the U.S. Constitution are particularly relevant in protecting these rights. Connecticut's criminal procedure also includes provisions for pre-trial motions, plea bargaining, jury selection, trial, sentencing, and the appeals process. State and federal court opinions continually interpret and apply these rules and Constitutional rights to ensure that the criminal justice system operates fairly and justly.