In 3-1 she had just received the news that Dahila was involved in Doug's murder the day before the trial. There was practically no time for her to try to find what the police didn't already collect.

And in 3-4, it was all just a flashback prompted by Phoenix looking at her old case files. Since it was her first trial someone else must've done the investigating beforehand. I doubt it though, because there was nothing else in the court record other than her badge and an autopsy report [far as I remember anyway].

And let's all forget that defense attorneys are "usually" prohibited from conducting their own investigations of the crime scene.