When a crime occurs, the police must conduct an investigation before making an arrest. The scope of this pre-arrest investigation can vary depending on the severity and complexity of the crime. In some cases, such as a reckless driving charge, a police officer may only need to interview witnesses and conduct a site investigation at the scene of the crime. However, for more serious crimes the police will need to investigate leads and gather physical evidence in order to build a strong case against the suspect.
In hit-and-run investigations, witness accounts are the most important element of the investigation. Witnesses can provide a number of critical details such as partial or full license plate numbers, driver descriptions, and directions in which the fleeing vehicle was traveling. It is essential that the police prioritize gathering these accounts immediately as human memory degrades quickly.
At the scene of the crime, the police will collect any physical evidence such as blood samples, fibers, footprints, or photographs. They will also look for any objects that could be used as weapons, such as broken door handles or bumpers.
Detectives will interview anyone that they believe could be a relevant witness, including victims and suspects. They will take careful notes and record everything that is said to ensure accuracy.
The police will then review the evidence gathered and prepare it for court. They will compile all reports, witness lists, and expert analyses into a file that they will present to prosecutors. The police and prosecutors will collaborate throughout the process to ensure that all elements of the case are ready for preliminary hearings, grand jury sessions, and the trial.