A criminal investigation is an official effort to uncover information about a crime. There are generally three ways that a person can be brought to justice for a criminal act. First, and probably the least likely, the individual will be driven by his conscience to immediately confess. Second, an officer of the law can catch him in the act. Third, and most common, a criminal investigation can identify him as suspect, after which he may confess or be convicted by trial.
In most cases, when a crime is committed, officials have two primary concerns. They want to know who committed the crime, and what the motive was. The reason why a person breaks a law is called the motive.
The motive does not always come after identifying the perpetrator in a criminal investigation. Sometimes the motive is suspected or known and used to catch the criminal. This is often true with crimes such as kidnappings and murders. Notes or other forms of evidence may be left that reveal why the crime has been committed.
Criminal investigations are usually conducted by police. There are other official agencies that have the authority to investigate and launch criminal charges. In the United States, these include the Federal Bureau of Investigation (FBI) and the Internal Revenue Service (IRS).
Police and other officials may use a variety of methods to conduct criminal investigations. Sometimes they work with their canine co-workers. They may also use various scientific techniques such as fingerprint and ballistics analysis.
A controversial investigation method sometimes employed in the US is the use of informants. Many people disagree with this practice because these individuals are generally criminals who are looking to get out of trouble or to reduce their punishments. It is therefore argued that they can be influenced to say or do whatever will please those investigating the case.
There are some parts of a criminal investigation that police may not be able to handle. Some cases require investigation techniques that demand specialized knowledge or training that the investigators or their colleagues may not have. This means that the police may have to employ others to help them. This is especially true with deoxyribonucleic acid (DNA) testing. Although this technique is popular, it is often performed by third-parties.
A criminal investigation does not always yield results. Sometimes suspects are accused only for it to be determined later that they are not guilty. At other times, an extensive criminal investigation may not produce any suspects. This can mean that no one will be punished for the crime that was committed.