A person of interest is someone involved in a criminal investigation whom the police would like to talk to. This term is sometimes used interchangeably with “suspect,” as in someone suspected of a crime, although a person of interest can also be a witness or someone else with supplementary information which might prove useful. Many law enforcement agencies prefer to use “person of interest” to avoid the negative connotations involved with “suspect,” to stress the idea that the person has not been accused of or charged with any crime.

When someone is named as a person of interest, it usually means that the police have identified some kind of connection between the individual and the crime. For example, in a kidnapping case, the parents are often persons of interest, because they may have important information which could help solve the crime. A person of interest might also be spotted by witnesses or seen on a surveillance tape. In all these instances, law enforcement agents simply want to get more information about the crime to assist with their investigation.

Sometimes, a person of interest is suspected of a more intimate involvement with the crime, in which case he or she may eventually be formally accused and brought to trial. Until a person of interest is positively identified as the accused, however, it is a bad idea to jump to conclusions about his or her involvement. Because much of the work of law enforcement is public, thanks to an eager press, police departments are often very careful about how they use language to stress this idea; they don't want vigilantes, for example, descending on the house of a person of interest in a murder case.

In most countries, a person of interest is entitled to certain legal protections. For example, while he or she can consent to questioning, law enforcement agencies cannot hold a person of interest for more than a few hours without evidence. A person of interest can also request the presence of a lawyer during questioning, especially if they feel that they might incriminate themselves in some way. If police want to hold a person of interest, they must be prepared to file charges.

Once someone who is suspected of a crime goes to trial, the rules change a bit. While being accused doesn't make someone guilty, it does mean that the police have firm evidence which suggests guilt, and the legal status of the person of interest changes significantly. If the outcome of a trial is a guilty verdict, the accused officially becomes the perpetrator, and he or she will probably have to submit to legal punishments such as jail time, a fine, or community service, depending on the nature of the crime.