Yes, luminol can pick up blood that is old or fresh. That would support TS's statement that Gannon had frequent nose bleeds and he hurt his foot in the garage or that there were tools laying around for people to cut themselves on and that there was likely blood everywhere in the house.A nurse friend of mine told me blood takes a very long time to dry and it reconstitutes very quickly. That's why it's so hard to clean up - when you wet dried blood again, it just gets all sticky and again, making it hard to clean up.
If there was a bloody beating Sunday night, blakets, sheets and such could stay wet or damp for a long time.
I asked her, if there were blood droplets found down the hall way----if they could be old from other beatings. She said yes, luminol will pick up traces old or new.
But I think that it is the specific locations, the amount of blood, and the blood spatter pattern that indicate most of the blood was from the murder. TS knew there would be a trail of blood. She specifically mentioned Gannon walking around the house to the gate over and over.
I believe that is the same path she took when she carried the body into the garage and put it in the back of her vehicle.
Imo