Investigation or Investigations may refer to:

Law enforcement

* Investigation, the work of a detective * Investigation, the work of a

private investigator A private investigator (often abbreviated to PI; also known as a private detective, an inquiry agent or informally a wikt:private eye, private eye) is a person who can be hired by individuals or groups to undertake investigatory law services. ...

Criminal investigation Criminal investigation is an applied science that involves the study of facts that are then used to inform criminal trials. A complete criminal investigation can include Search and seizure, searching, interviews, interrogations, Evidence (law), ...

, the study of facts, used to identify, locate and prove the guilt of an accused criminal *

Criminal investigation department The Criminal Investigation Department (CID) is the branch of a police force to which most plainclothes criminal investigation, detectives belong in the United Kingdom and many Commonwealth of Nations, Commonwealth nations. A force's CID is disti ...

, the branch of British Police force to which plainclothes detectives belong *

Federal Bureau of Investigation The Federal Bureau of Investigation (FBI) is the domestic Intelligence agency, intelligence and Security agency, security service of the United States and Federal law enforcement in the United States, its principal federal law enforcement ag ...

, the primary investigative arm of the US Department of Justice * Tax investigation

Medicine

Clinical trial Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...

, an investigation conducted to collect data for new drugs or devices * Investigational New Drug, a category in a USFDA program * Outbreak Investigation

Science and maths

Forensic science Forensic science combines principles of law and science to investigate criminal activity. Through crime scene investigations and laboratory analysis, forensic scientists are able to link suspects to evidence. An example is determining the time and ...

investigation, in fields such as accounting, science, engineering and information technology *

Investigations in Numbers, Data, and Space Investigations in Numbers, Data, and Space is a K–5 mathematics curriculum, developed at TERC in Cambridge, Massachusetts, United States. The curriculum is often referred to as ''Investigations'' or simply ''TERC''. Patterned after the NCTM sta ...

, a K-5 mathematics curriculum

Arts, entertainment, and media

Literature

* '' The Investigation'', a 1959 book by Stanisław Lem * ''The Investigation'' (play), a 1965 play by Peter Weiss

Television

* "Investigations" (''Star Trek: Voyager''), an episode of the television series ''Star Trek: Voyager'' * Investigation (TV channel), a Canadian French-language specialty channel * ''The Investigation'' (TV series), a 2020 six-part Danish TV series *

Investigation Discovery Investigation Discovery (stylized and branded on-air as ID since 2008) is an American multinational pay television network dedicated to true crime documentaries, similar to corporate sibling HLN. It is owned by Warner Bros. Discovery's netw ...

, a digital cable channel

Other uses in arts, entertainment, and media

* "Investigations", a 2009 song by Kevin MacLeod * ''Investigate'' (magazine), a New Zealand current affairs magazine * ''Investigation'' (film), a 2006 Bulgarian drama * Investigative journalism, the practice of in-depth reporting or analysis * Temporal Investigations, an agency of the government of the United Federation of Planets in the fictional universe of ''Star Trek''