that killed Sahra. Compare what the "AS" said to Sahra vs. what Mesaana demanded of Alviarhin:

“Every person this Elmindreda spoke to, every word she said, every nuance and expression.”
On her knees, Alviarin repeated every word that Elaida had said, though she wondered why it was necessary. In the beginning she had left out unimportant bits, and Mesaana knew every time, demanded every word, every gesture and facial expression.


One thing that people forget is that Siuan was very carefully hiding her tracks, and had sent Sahra to that farm in utmost secrecy. As few people as possible would have known where Sahra was, and finding out would have taken some considerable digging through personal info. (Like searching through Siuan's papers in TAR. And you have to remember that this was back in tSR, long before it came into widespread use later in the series.)