Kainon

Kainon was a criminal Bajoran, a humanoid alien race from the immensely popular sci-fi franchise Star Trek : he was a murderous racist and is most known for fatally stabbing Aamin Marritza simply for being Cardassian, although the hatred was stemmed from years of atrocities by Cardassians his actions were inexcusable and fueled purely out of xenophobia.

History
(information taken from Memory Alpha wiki, to be modified soon in accordance to Villains Wikis policies)

was a Bajoran citizen alive during the late-24th century. By his later life, he had developed a history of committing minor criminal offenses.

In 2369, Kainon was living on Deep Space 9 when he was detained for public drunkenness and placed into a holding area with the Cardassian Aamin Marritza. Kainon became quite vocal in his displeasure at having to share his cell block with a Cardassian.

After Marritza was released, Kainon, in his disdain for Cardassians, fatally stabbed Marritza declaring, "He's a Cardassian. That's reason enough!" Constable Odo then escorted Kainon back to his cell.