This might be a case of high velocity blood spatter. This type of blood stain is most likely to be caused by a gun of a small calibre. The gunshot usually causes high velocity blood spatter or can be caused by other objects when high amount of force is exerted. The high velocity blood spatter are caused by force travelling at a speed of 100 feet per second or more which produces droplets of diameter less than 1 mm. Explosions may also cause such high velocity blood spatter.