At the beginning of WoT Book 11, "Knife of Dreams", Galad Damodred challenges Eamon Valda to a duel in retribution for
the murder and rape of his step-mother, Morgase Trakand.
The rumor of murder was well-known by the time, but very few people (at most the five with her at the time, and likely only two of them) knew about her treatment at the hands of Eamon Valda, although Galad clearly makes reference to her "abuse" as well as murder:
“A Child of my command charges another of the Children with abusing a female relative of his, and claims the right of Trial Beneath the Light, which by law you must grant or deny.”
This begs the question, how did Galad find out about Morgase's treatment while being held by Eamon Valda?