reports and said it wasn't a murder. >> is blood in all of the ventricles of the brain consistent with a stroke from natural causes? expert: it is consistent. >> reporter: then, there was the mount everest of the case: the forensics, explaining to the jury all that blood in the peterson stairwell. >> the defense would call dr. henry lee to the stand. >> reporter: the defense called celebrity forensic expert dr. henry lee, of o.j. case fame, to show the jury in theatrical fashion just how kathleen, falling, then staggering about, coughing up blood, could have accounted for the spray. >> an injured person can walking, can move, can shake their head. >> obviously, the blood all around was due to her being alive and moving around for some period of time. it didn't have to do with what inflicted the wounds. >> reporter: the blood on his shorts, that could have happened, thdense said, while michael peterson was