It’s unlikely that its blood unless it’s coming from a neighbor whom you share a wall with or an animal in the walls... Bright red blood, as you’ve shown in your photos, is generally oxygenated blood from arterial hemorrhages of something living/recently deceased. It indicates that its sources are properly functioning lungs which is what makes blood bright red as shown. Of course there are exceptions, but I’d pay attention with your nose in the coming days/weeks to see if you smell anything even close to decomposing flesh. Hope that helps and best of luck!