When police receive a report of a crime, they begin an investigation. The process involves collecting evidence and interviewing witnesses. The goal is to prepare a criminal case that will stand up in court.
Investigations often start with the physical collection of evidence at a crime scene. This may include obtaining photos, measurements and objects. Detectives document these items for later use. They also analyze the crime site for any physical clues to identify and locate suspects. Investigators use information gathered from the scene, witness statements and witness interrogations to build a suspect profile. This information helps them determine the method and motives behind the crime.
Investigators may check databases such as CODIS and the Integrated Ballistic Identification System for links to other crimes. They may also check public tips and informants for possible suspects. They can request a search warrant for an individual’s home, clothing or vehicle, but they must have probable cause and a judge’s approval. Law enforcement officials also go undercover in drug offense and pornography cases to gather information.
Throughout the process, investigators collaborate with legal professionals to ensure that all components of a case meet the burden of proof necessary for conviction. This collaboration can help prevent missteps like reluctant witnesses or insufficient forensic results from spoiling an otherwise strong case. Detectives can also help prosecutors by helping them prepare for pretrial hearings, grand jury sessions and the trial. It is crucial that all information and evidence be collected properly, documented and stored in order to preserve its integrity.