Generally speaking, an investigation begins when police officers visit the scene of a crime. They’ll speak with the victim or witnesses to gather statements, and if necessary, collect physical evidence. They’ll document what they see, including weapons used in the incident and blood stains on the ground.
Police investigators also interview suspects and others who may have information on the case. These interviews are not casual conversations; they’re structured and meant to extract specific pieces of information from the person being interviewed.
Once they’ve got all this information, a detective will develop a strategy to solve the case. This may include further surveillance, sting operations, or undercover work. They will then seek a warrant for the suspect’s arrest or search and seizure activities from a judge after presenting probable cause for those requests.
Throughout the entire process, detectives will work hard until all known leads are exhausted and they have enough evidence to bring the suspect to trial. They’ll present all the evidence to a prosecutor, who will direct them regarding which people they should interview in connection with the case and what kind of questions should be asked.
In some cases, the police might need to consult with a specialist on technical, chemical or biological issues that have a significant impact on the investigation. This is often the case for narcotics investigations and other cases involving serious crimes, such as homicide or robbery. A specialist can provide valuable insight into the nature of an offence, helping investigators make a more successful case in court.