C&P from ME-Wiki:
In Mass Effect: Redemption the Shadow Broker was hired by the Collectors to retrieve Shepard's body and deliver it to them. As Harbinger is talking about the deal to the Shadow Broker, only one voice is responding to the possessed Collector General further hinting that the Shadow Broker is indeed a singular individual. He sent Tazzik, his personal enforcer, to retrieve Shepard's remains from the Blue Suns on Omega, a task at which he succeeded despite interference from Liara T'Soni and Feron. When the two followed Tazzik to the Broker's base on Alingon, they come face-to-face with the Broker, so to speak, as an obscure shadowy figure. Liara talked to him while Feron downloaded all the informing on the Broker's dealings with the Collectors. When asked to why he would sell Shepard to the Collectors, who may be working for the Reapers, the Broker answered that it was simple business. He doesn't believe that the Collectors could gain anything from a corpse. When Liara got close enough to get a good look at the Broker, she finds that it is a just a machine he's communicating through. But before the Broker could alert his men to their presence, Feron had finished downloading and Liara unleashed a powerful display of biotics, disabling the communications in the room. When they attempt to fool Tazzik and the Collector intermediary into thinking the Broker wanted full payment, the Collector General, who was possessing the drone, accused the Broker of treachery. The Broker assured the Collector that Feron doesn't speak for him. Despite the General's warning, Liara is able to escape with Shepard's body, but is forced to leave Feron behind.
(
http://masseffect.wikia.com/wiki/Shadow_Broker)
Liara confesses that she feels guilty — she understood that Cerberus would use Shepard for their own agenda, but nevertheless gave the Commander's body to the Illusive Man, because she could not let Shepard go. Shepard may choose to calm her by assuring that she did the right thing as the current mission is extremely important. After handing over Shepard's body, Liara remained on Illium, devoted to hunt the Shadow Broker down, although she expresses regret that she cannot come with Shepard.
(
http://masseffect.wikia.com/wiki/Liara)
Basically Liara loved you so much that she rescued your body from the Shadow Broker and the Collectors and gave it to the Illusive Man's Lazarus Project so that you could live again. She has since become violent in her quest for revenge against the Shadow Broker.