Klingon Intelligence
Klingon Intelligence was the intelligence gathering agency of the Klingon Empire responsible for conducting espionage and covert activities.  Since espionage was, in itself, considered by the Klingons as a somewhat dishonorable activity, agents who failed to accomplish their mission were dishonored and frequently exiled from the Empire. ()

Arne Darvin was an agent in Klingon Intelligence, surgically altered to appear Human. He was assigned in 2268 to poison a shipment of quadrotriticale bound for Sherman's Planet. Darvin's identity was discovered when a tribble reacted to him. (; )

In 2371, Klingon Intelligence sent agents Bo'rak, Atul, and Morka to Deep Space 9, aboard a broken-down freighter, to observe a Romulan delegation being briefed by Starfleet concerning the Dominion. They planted a surveillance device near the Romulan's quarters by modifying a replicator into a transporter. Their identities were exposed after Miles O'Brien witnessed himself being killed by the surveillance device's booby-trap mechanism in the future. ()

In 2372, Klingon Intelligence had discovered that the Cardassian planet Loval was the site of a secret weapons research facility, which led a Klingon Bird-of-Prey to attack the planet. ()

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de:Klingonischer Geheimdienst
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Intelligence agencies