Jerralyn Merritt explains who needs to show what at George Zimmerman's June 29th bond hearing. Her gist - normally a defendant is entitled to reasonable bail. This is not the case with a Murder Two charge. However, even then the state has the burden to demonstrate a strong case, and precedent suggests that plausible self-defense claims reduce a case from strong to arguable.
So it seems to me Zimmerman is still entitled to release on bond. And Judge Lester's order [link] yesterday [where he described the stat'e case as "strong"] contains a revisionist view of what he ruled on April 20.