Some argue that criminal investigation dates to ancient times as far back as 1700 BCE and that it is contained in the writings of the Code of Hammurabi, which suggest that ‘’both the accuser and the accused have a right to present the evidence they collected’’. Today, criminal investigation is used as a scientifically method applied mostly by criminal investigators, police officers, as well as private investigators. Criminal investigation became an integral part of fair and effective criminal justice system with a goal of building public confidence and encouraging the respect for order and law in societies.
Criminal investigation can be defined as a collection of methods used for studying crimes that have been committed. It is a process of collecting information and evidence to establish if a crime has been committed, identify and apprehend the perpetrator, and provide evidence to support a conviction in court. As defined by the United Nations ‘’criminal investigation is the process by which the perpetrator of a crime, or intended crime, is identified through the gathering of facts or evidence’’. During this process, criminal investigators determine the methods, motives, and identities of both perpetrators and victims. Basically, they look for clues and evidence to establish whether a crime has taken place. If a crime has been committed, investigators often start their investigation by looking into the background of the suspected person to try to uncover the facts about the crime. Criminal investigation can be reactive, which means that it is applied to crimes that have already been committed, and proactive, through targeting a specific criminal or forestalling a criminal activity planned for the future. The types of investigation that fall under the scope of criminal investigations are:
- fraud investigations
- crime scene investigations
- sexual crime investigations
- theft investigations
- kidnapping investigations
- assault investigations
- criminal defense investigations
Criminal investigators collect information on criminal activities that took place and that are later prosecuted in the court. This makes the investigative process subject to extensive legal scrutiny. However, prior to being prosecuted, a suspected person must be charged with committing a certain crime and there has to be a probable or reasonable cause that he or she committed a crime before they can be arrested. Criminal investigators are, therefore, in charge of showing that the accused person participated in what constitutes the elements of the crime. For example, to prove that a suspect committed a theft, a criminal investigator has to prove that a suspect conducted a theft in the presence of the victim against their will by using force or the threat of force. All the evidence that was gathered during the investigation is presented to the court and a decision is made in regard to punishment.
There are two basic approaches to managing a criminal investigation. In some countries where a civil law tradition is typical, the responsibility for an investigation is given to a public prosecutor or a judge. In these circumstances, investigators work under the management of the prosecutor or a judge. The second approach that is applied to criminal investigations is usually found in countries with a common law tradition where investigations are conducted by the police independently of prosecutors until a suspect is handed over for prosecutions in the course. Nevertheless, these approaches are not ultimate since there are variations in every system, such as for example those in which prosecutors will closely work with police on certain criminal events. Regardless of which approach is applied the basic tenet remains that during the criminal investigation investigators are responsible for identifying who committed the criminal act and gather sufficient evidence to ensure a conviction.
To be able to conduct criminal investigations effectively, investigators apply considerable powers such as detaining a suspect, seizing property as evidence and searching for evidence in premises and on person, interviewing suspects and victims, as well as requiring samples such as fingerprints and DNA and taking photographs, running identification procedures, interviewing witnesses and asking questions members of the public. During these activities, investigators are obliged to keep and maintain confidential information. They might also be required to use personal and technical surveillance and other intrusive means to observe suspected persons, work undercover or use informants. Their scope of work also expands to protection and reallocation of witnesses. In some occasions, investigators are in need to call on international assistance to track activities of suspects across international borders. This type of cooperation is usually coordinated by international organizations or bilateral agreements, accessible to any investigator working at a local level.
While conducting an investigation, a criminal investigator always has to keep in mind his or her duties which require them to be fair, impartial and unbiased. Investigators are obliged to develop leads that indicate innocence of a suspected person as much as they are obliged to collect evidence that will prove them guilty. If an investigator does not consider or take into account all the facts and evidence, then they are being unfair, and the investigation may result in the conviction of an innocent person.
One of the issues that may appear during the course of criminal investigation is that there are potentially massive amounts of information available, however, the relevance of the information collected remains unknown since it is often incomplete and, in some cases, inaccurate. To be useful in court, the evidence has to contain certain qualities, and investigators have to follow certain rules and procedures while collecting the evidence.
Nevertheless, all investigators are more effective when they have certain physical, psychological and intellectual characteristics. Those who are proven to be effective, work to obtain and retain information while applying their technical knowledge and remaining open-minded, objective and logical. Criminal investigators should be also emotionally well balances, detached, suspecting, preserving, self-disciplines, and inquisitive. Last but not least, when conducting criminal investigations, investigators should be able to interact across ethnic, gender, generational, political and social group lines.