I believe that it's highly unlikely that large pools of blood, or anything like that were found. The hardwood flooring and textured sheetrock walls would be difficult to clean so well that neither CB or the police spotted anything at all. I also believe that the reason the second search was conducted at night was because Luminol works better in the dark, especially for locating minute splatters. However, Prosecutor May's Assistant DA explained in a news conference that the reason they dropped objection to the "Order Preservation of Physical Evidence" was that the minute pieces of evidence that they thought they were going to use had proved not to be evidence after all, and that although they did reserve the right to bring the matter up again, they didn't anticipate having any evidence in the future that might be small enough to be destroyed in testing.
Let's speculate that they found nothing at all in forensic matter worth introducing in court. They can still proceed, if they other evidence that is strong.
CSI style forensics has solved many a murder case, but there are still people around who remember when "Forensics" meant blowing charcoal dust all over everythning, making a bunch of gooey impressions, and shipping them off to the FBI lab in Virginia for fingerprint matching. Somehow, prosecutors found ways to convict most of the guilty parties. It certainly will be interesting when this case is finally laid out. IMO