Absence of bright red blood means that the bleeding has reduced in quantity.
Blood gets altered in the bowel to black colour as it passes though the colon.But if there is too much of blood , then some part of it comes out unchanged and you pass red blood. If bleeding decreases then it may be just black stools.
Another possibility is there were two sources of bleeding - one high up in bowel and one lower down. Bleeding from the lower down is red and bleeding from higher up is usually black. So if the lower down bleeding has stopped the red blood may stop and black stools will continue due to the blood from the higher up.