In the Star Trek: The Next Generation episode “Reunion”, we end up saying goodbye to three prominent Klingon characters: K’Ehleyr, K’mpec, and Duras. K’mpec had been slowly poisoned for months through trace elements planted in his bloodwine. He died believing that one of the two candidates for chancellor-- Gowron or Duras-- had been behind the poisoning.
What follows is one of the best episodes of TNG in my opinion-- full of the political intrigue that would later become a mainstay in DS9’s best seasons. A suicide bomber attacks during the Son’chi ceremony. We find out later that the suicide bomber was probably one of Duras’ men. Gowron goes to K’Ehleyr and tries to bribe her, and later threaten her, to use her influence with Picard to have Gowron named chancellor. He uses the words “K’mpec was stubborn too; he also refused to listen.” Makes you think he may have had a hand in the poisoning, doesn’t it?
Worf refuses to speak to K’Ehleyr about his discommendation, leading her to investigate the matter herself. When Duras realizes she’s been poking around, he confronts her, and she tells him what he’s discovered. So he kills her. Worf gets to her in time for her to name her murderer, and Worf goes over to Duras’ ship and avenges her death.
Later, in “Redemption, Part I”, Gowron says to Worf, “You killed Duras, and I consider that no small favor.”
But hooooold on a second. Duras may have died in disgrace, but we never got an answer to the question of who killed K’mpec. In fact, the evidence seems to point to Gowron as the likely suspect. And the Gowron we see later in TNG and DS9 is a manipulative political animal; I wouldn’t put it past him!