Private investigator in the context of "Cormoran Strike"

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 searching, interviews, interrogations, evidence collection and preservation, and various methods of investigation. Modern-day criminal investigations commonly employ many modern scientific techniques known collectively as forensic science.

Criminal investigation is an ancient science that may have roots as far back as c. 1700 BCE in the writings of the Code of Hammurabi. In the code, it is suggested that both the accuser and the accused had the right to present evidence they collected. In the modern era, criminals investigations are most often done by government police forces. Private investigators are also commonly hired to complete or assist in criminal investigations.

The Spirit is a fictional masked crimefighter appearing in American comic books. Created by cartoonist Will Eisner, he first appeared as the main feature of a tabloid-sized comic book insert distributed in the Sunday edition of Register and Tribune Syndicate newspapers. Popularly referred to as "The Spirit Section", the insert ran from June 2, 1940 to October 5, 1952.

The Spirit is the alias of Denny Colt, a private investigator and criminologist based in the fictional Central City, who falls into suspended animation while trying to apprehend the mad scientist Dr. Cobra. Officially pronounced dead, Colt revives after being interred in Wildwood Cemetery. With the blessing of his old friend, police Commissioner Eustace Dolan, Colt becomes a domino mask-wearing "friendly outlaw" who pursues criminals that might otherwise escape capture by traditional law enforcement. The Spirit usually does not possess any superpowers, but relies on his wits and physical prowess, as well as the myth of his supposed resurrection, in his battles against evildoers. He frequently encounters femme fatales over the course of his adventures, including serial seducer P'Gell, thief-turned-troubleshooter Silk Satin, and his estranged childhood friend Sand Saref; he also comes into conflict with his archenemy the Octopus, an unseen criminal mastermind. Other supporting characters include Ellen Dolan, Commissioner Dolan's headstrong daughter and the Spirit's primary love interest, and his recurring sidekick Ebony White, a young, diminutive cab driver.

Sherlock Holmes (/ˈʃɜːrlɒk ˈhoʊmz/) is a fictional detective created by British author Arthur Conan Doyle. Referring to himself as a "consulting detective" in his stories, Holmes is known for his proficiency with observation, deduction, forensic science and logical reasoning that borders on the fantastic, which he employs when investigating cases for a wide variety of clients, including Scotland Yard.

The character Sherlock Holmes first appeared in print in 1887's A Study in Scarlet. His popularity became widespread with the first series of short stories in The Strand Magazine, beginning with "A Scandal in Bohemia" in 1891; additional tales appeared from then until 1927, eventually totalling four novels and 56 short stories. All but one are set in the Victorian or Edwardian eras between 1880 and 1914. Most are narrated by the character of Holmes's friend and biographer, Dr. John H. Watson, who usually accompanies Holmes during his investigations and often shares quarters with him at the address of 221B Baker Street, London, where many of the stories begin.

The Intelligence field, in simplistic terms, is a collection of the people who gather or sift through intelligence. Those persons popularly called "spies" are a small but important part of the intelligence field. The intelligence field is the top-level field composed of people and organizations and their involvement the systematic espionage, analysis, and dissemination of intelligence to support policymaking and key stakeholder decision-making, primarily in matters related to national security, military affairs, law enforcement, and international relations. Collectively, that process of intelligence is usually called the intelligence cycle. The intelligence field can encompass a range of subfields including; espionage, surveillance, data analysis, and counterintelligence, all aimed at understanding threats, opportunities, and the intentions and power projection of foreign entities. While the act of espionage is illegal throughout the world, espionage is only a single subfield of the intelligence field. There are many subfields of intelligence that are not illegal everywhere, such as Open-source intelligence (OSINT).

Intelligence work can be conducted by government intelligence agencies, police forces, and military intelligence units. This work can also be engaged by private organizations, including; private intelligence agencies, multinational corporations, private investigators, drug cartels, narcotic cartels, terrorist groups, and others. Individuals employed by these organizations can either be fully employed officers of intelligence agencies called intelligence officers, or single and mission-specific solitary contracting agents who are commonly known as "secret agents." Confusingly, the term "spy" has no definition at most intelligence agencies, but is codified in many state judicial systems as an illegal operator.

A detective is an investigator, usually a member of a law enforcement agency. They often collect information to solve crimes by talking to witnesses and informants, collecting physical evidence, or searching records in databases. This leads them to arrest criminals and enable them to be convicted in court. A detective may work for the police or privately.

James Scott Garner (né Bumgarner; April 7, 1928 – July 19, 2014) was an American actor. He played leading roles in more than 50 theatrical films, which included The Great Escape (1963) with Steve McQueen; Paddy Chayefsky's The Americanization of Emily (1964) with Julie Andrews; Cash McCall (1960) with Natalie Wood; The Wheeler Dealers (1963) with Lee Remick; Darby's Rangers (1958) with Stuart Whitman; Roald Dahl's 36 Hours (1965) with Eva Marie Saint; as a Formula 1 racing star in Grand Prix (1966); Raymond Chandler's Marlowe (1969) with Bruce Lee; Support Your Local Sheriff! (1969) with Walter Brennan; Blake Edwards's Victor/Victoria (1982) with Julie Andrews; and Murphy's Romance (1985) with Sally Field, for which he received an Academy Award nomination. He also starred in several television series, including popular roles such as Bret Maverick in the ABC 1950s Western series Maverick and as Jim Rockford in the NBC 1970s private detective show, The Rockford Files.

Garner's career and popularity continued into the 21st century with films such as Space Cowboys (2000) with Clint Eastwood; the animated film Atlantis: The Lost Empire (2001) (voice work) with Michael J. Fox and Cree Summer; The Notebook (2004) with Gena Rowlands and Ryan Gosling; and in his TV sitcom role as Jim Egan in 8 Simple Rules (2003–2005).

Doctor Occult (Richard Occult, sometimes nicknamed the Ghost Detective, and one time referred to as Doctor Mystic) is a superhero appearing in American comic books published by DC Comics. Created by Jerry Siegel and Joe Shuster (the creators of Superman), Doctor Occult is an occult detective, private investigator and magic user who specializes in cases involving the supernatural. Doctor Occult first appeared in 1935 during the Platinum Age of Comic Books. He was published by National Comics Publications and Centaur Publications within anthology titles. He is the earliest recurring, originally featured fictional character still used in the DC Universe. He is sometimes affiliated with the All-Star Squadron and has appeared in paranormal-related stories by DC and Vertigo Comics titles.