A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Atarah al'Norahn
He was killed in the Two Rivers by the Whitecloaks; they caught him crossing an open field. Alanna felt every arrow that struck him until he died, but as she was not there, she could do nothing to defend him (TSR, Ch. 31).
Alanna allows herself to weep occasionally since leaving the Two Rivers (LoC, Ch. 11). Some of the other Aes Sedai have differing opinions of what Alanna is feeling with Owein's death; Merana thinks that Alanna deserves a little upset for bonding Rand against his will, even if she did just recently lose a Warder, but Seonid speaks almost gently to her (LoC, Ch. 43).