After listening to the testimony below, I believe there would have been blood IMO If you don't want to watch it all, watch part 2 around 41:00, and the beginning of Part 3. McGee goes through all the skull fractures/impacts. She says which one's she would expect to see a laceration due to the force. IMO the chances that there would be no blood is pretty small, if it was just 1 victim, maybe, but with all 4, the chances that all 4 didn't bleed, I find that hard to believe, again, JMO. We have also heard from some of the detectives... Steers is one of them IIRC, that agreed, in his experience, he would have expected to see blood at the crime scene, which is why they went back to the Fallbrook house in 2014.
Dr Chanikarn Changsri - Chief Forensic Pathologist at Coroners office.