Tarsus IVedit

From Memory Alpha, the free Star Trek reference

Tarsus IV was the site of a Federation colony in the 23rd century, the fourth planet of the Tarsus system. In 2246, an exotic fungus destroyed most of the colony's food supply, leaving the 8,000 colonists in serious danger of starvation. Governor Kodos made a drastic decision: he ordered the deaths of 4,000 colonists, so that the other 4,000 might live, selecting those to be killed according to his personal theories of eugenics. Earth forces arrived earlier than expected, but too late to save the 4,000 people Kodos murdered. All that was found of Kodos was a burned body, and he was presumed dead, until his chance discovery on Planet Q twenty years later.

Amongst the survivors of the Tarsus IV incident were James T. Kirk, Kevin Riley and Thomas Leighton, who were three of only nine survivors who knew Kodos' face, and would be able to identify him. (TOS: "The Conscience of the King")

Tarsus IV also appeared in the starchart Data and Picard were studying in Stellar Cartography in 2371. (Star Trek Generations)