Did the colonists know about the Zerg?[]
Yes.
According to the manual, they had been wiped out before the protoss even got there. Any survivors would have known about them.
According to Loomings, the zerg attacked the biggest cities. Cerberus sealed off communications, but that was only after the main city was saved. Kimera 757 (talk) 22:05, 27 October 2008 (UTC)
Some weirdness after the edits[]
I suggest that the page be reverted to the way it was before the end of October. Some redundancies and other minor errors have been inserted during the edits on Oct. 28. capefeather 22:44, 22 November 2008 (UTC)
Number of colonists killed by the Zerg[]
"The entire surface of the colony had been covered with a thick, toxic substance that continued to erode the planet’s crust. To make matters worse, the aliens themselves had either infested or slaughtered most of the human colonists."
And that's the only thing the manual says about the number of colonists wiped out on Chau Sara by the time of the purification. Besides, we can try common sense: if all of the colonists were already wiped out, Tassadar wouldn't have any regrets about incineraing Chau Sara. XEL 14:20, January 2, 2011 (UTC)