Unidentified decedent or unidentified person (also abbreviated as UID or UP) is a term in American English used to describe a corpse of a person whose identity cannot be established by police and medical examiners. In many cases, it is several years before the identities of some UIDs are found, while in some cases, they are never identified. A UID may remain unidentified due to lack of evidence as well as absence of personal identification such as a driver's license. Where the remains have deteriorated or been mutilated to the point that the body is not easily recognized, a UID's face may be reconstructed to show what they had looked like before death. UIDs are often referred to by the placeholder names "John Doe" or "Jane Doe".