User blog comment:Fijibuffman1925/Lucy's Betrayal/@comment-27202257-20140701183306/@comment-27202257-20140702060339

One more thing: Desmond actually figured out that Lucy was a traitor from Juno, because apparently she showed Desmond what Lucy would do with the Apple and therefore convinced him to kill her. Then, yeah, he got the details from Clay and communicated all that to the team, but as Kain said he apparently did it right as they were arriving at the Temple.

Honestly, this was one of the biggest disappointments in AC3 for me. Not only did it blow the whole Lucy revelation and make it look like Desmond and company barely cared, but it retroactively ruined the ending of Brotherhood by saying oh actually, Desmond totally MEANT to do that. Yep. Definitely.