Covert listening device

A covert listening device, more commonly known as a bug or a wire, is usually a combination of a miniature radio transmitter with a microphone. The use of bugs, called bugging, is a common technique in surveillance, espionage and in police investigations.

A bug does not have to be a device specifically designed for the purpose of eavesdropping. For instance, with the right equipment, it is possible to remotely activate the microphone of cellular phones, even when a call is not being made, to listen to conversations in the vicinity of the phone.

A "wire" is a device that is hidden or concealed under a person's clothes for the purpose of covertly listening to conversations in close proximity to the person wearing the "wire". Wires are typically used in police sting operations in order to gather information about suspects.

The act of "wearing a wire" refers to a person knowingly recording the conversation or transmitting the contents of a conversation to a police listening post. Usually, some sort of device is attached to the body in an inconspicuous way, such as taping a microphone wire to their chest. "Wearing a wire" by undercover agents is typical plot element in gangster and police related movies and television shows.

A stereotypical movie scene is someone being suspected of "wearing a wire" and the criminals tearing the suspect's shirt open hoping to reveal the deception.

When infiltrating a criminal organization a mole may be given a "wire" to wear under his or her clothes. The wire device transmits to a remote location where law enforcement agents monitor what is being said. Wearing a wire is viewed as risky since discovery of a hidden wire by a criminal could lead to violence against the mole or other retaliatory responses.

Mobile phone (cell phone) microphones can be activated remotely, without any need for physical access. This "roving bug" feature has been used by law enforcement agencies and intelligence services to listen in on nearby conversations. A United States court ruled in 1988 that a similar technique used by the FBI against reputed former Gulfport, Mississippi cocaine dealers after having obtained a court order was permissible.

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Wikipedia