It would make sense to me that she or her family were doing a search for Jose before her second arrest if not sooner. Internet search could have pulled him up, one of Casey's family doing work from the outside (not sure if inmates are allowed to use the internet) or possibly she could have done it herself.
It seems likely this might have been the case since it would have given him more time to look over the case to decide if he was going to take it. This is probably why she filed for a public defender. Because either she didn't have his fee yet, or he wasn't sure if he wanted to get into the hot mess that he suspected would be this trial. Maybe he realized that even though it was a hot mess, that this would have the potential to throw him into the lime light.
It is not difficult to think that this case would get more attention since the case had been in the media off and on, and it would be getting at least some follow up. As well, Casey had no offical story of what happened to Caylee once the Nanny kidnapped my kid fell through. I think this was a big bonus for Jose.
The question does stand to reason though. Who is paying Jose for Casey or is he doing this pro-bono?