Criminal Investigation Department

The Criminal Investigation Department (CID) is the branch of a police force to which most plainclothes detectives belong in the United Kingdom and many Commonwealth nations.

The name derives from the CID of the Metropolitan Police, formed on 8 April 1878 by C. E. Howard Vincent as a re-formation of its Detective Branch.

Kriminalpolizei is the standard term for the criminal investigation agency within the police forces of Germany, Austria, and the German-speaking cantons of Switzerland.

Many state police forces in India possess a CID (sometimes known as the investigation branch) as a specialised wing.

Officers and men attached to this wing generally add the prefix detective before their regular police rank.

In Assam, Bihar, Haryana, Uttar Pradesh, Rajastan, West Bengal, Maharashtra, Karnataka and Jammu and Kashmir, it is known as the Criminal Investigation Department.

Crime Detachment and Crime Squads are a group of regular law and order policemen (who generally wear the uniform specifically detailed by the police inspector to work in plain clothes to keep a tab on local criminal elements, prostitutes, petty thieves, and other habitual offenders.

Every regional police force in Indonesia has this unit; they are concerned with conducting criminal investigations and identification activities.

The Royal Irish Constabulary (RIC) maintained a CID along British lines before the independence of most of Ireland in December 1922.

In Northern Ireland, a region that came into existence in 1921 and which has remained within the United Kingdom, a new police force was formed in June 1922 called the Royal Ulster Constabulary (RUC).

A particular case would be assigned to a Senior Investigating Officer (SIO) whose rank would depend on the seriousness of the crime and their force's policy.

Ranks are abbreviated as follows: To join a CID in the United Kingdom, a police officer usually must have served in uniform for at least two years.