Hi Dunlurkin, From what I read here late last night, blood does not decompose but starts breaking down immediately upon death. The poster {name? ;} said blood is mainly red blood cells and water, and as this breaks down it joins with the body fluids that escape from the tissue cells that burst in the decomposition process.
That would lead me to believe the blood one sees pooling around a dead body would be there from the pull of gravity and not pumped out as it would be on a bandaid. All that blood would not have a chance to start breaking down in the body before it leaked out. As such, wouldn't that be classified as 'live' blood?
Also, it takes between 1 1/2 to 2 hours before the death scent has been established to where a cadaver/human remains recovery dog can sniff it.
That is my stab at it. I hope the poster from last night who seemed an expert on the subject will post here again today. ;}