There are a number of principles, based on experience and practice that should be used as guidelines by the Private Investigator. These can be summarised as follows:
- An investigation is a search for the truth, with a view to determining whether there has been any breach of the law, or alternatively to determine responsibility for the occurrence of an event. The gathering of the evidence to achieve that objective must at all times be obtained within the limits of established rules of law and procedure. That means that the investigation has to be carried out in accordance with certain rules and procedures.
- The Private Investigator has the responsibility for conducting the investigation into a particular crime or event. To be successful, the private Investigator must be completely objective. No matter what the circumstances, it is imperative to keep an open mind. It must be remembered that the goal is as much freeing a person from blame as it is with gathering the evidence to show that a person may be responsible for a particular crime or event. The Private Investigator is an impartial collector of evidence and is not the judge.
- In the case of a crime it is a fundamental rule of any investigation that the Private investigator must first establish whether or not a crime has actually been committed or an event has actually occurred. Once that has been established, then the goal is to set about identifying the offender and the whereabouts of that person.
Evidence consists of
- Physical Exhibits
All of which may be legally admitted in order to prove or disprove the facts under enquiry.
There are seven basic sources of evidence that the investigator has recourse to during the course of an investigation. These are:
- A search of the scene of the crime or event
- Examination of exhibits
- Interviewing witnesses
- Information received – informers, the public and colleagues
- Inspection of official records
- Surveillance of suspects, premises or vehicles
- Interview of suspects
When given the opportunity to search the scene 針孔 of a crime or event, then that search must be exhaustive. As the investigator, you must be satisfied that you have found any evidence that is capable of being found.
Physical evidence is real evidence. It always tells the same story and is not subject to the adverse influences that affect human memory.
Science and technology are aids to, and not substitutes for, investigation. The investigator must discover the physical evidence for submission to experts.
The evidence of witnesses is affected by human frailty. Every effort must be made to obtain confirmation of what witnesses have said in their statements. Investigation occurs against a legal background which governs investigative procedure. Two traditional common law principles operate in favour of persons suspected or accused of crime in order to protect the innocent. These are:
The presumption of innocence – The rule against self-incrimination
The law not only presumes that every person is innocent of any crime until the contrary is proved beyond reasonable doubt, but also that no person shall be bound to incriminate himself. As a result, having established that a crime has been committed, the Private Investigator must be able to prove any criminal charge which arises, beyond reasonable doubt and, if necessary, in the absence of any admission or confession from the accused.