Bloodstains falling from a moving body indicate speed and direction.

Spurts of blood falling onto a flat surface such as a wall  from a stationary body usually form a series of linear streaks which are widened, club-like, at their lowest end.

A single spot of blood falling vertically to the ground will usually form a perfect circle if the drop is not far, from a greater height the drop becomes more "splattered" around its edges.

If someone is moving, a falling drop of blood will look rather like an exclamation mark, with the dot marking  the direction of the path of the drop of blood. Smears of blood similarly indicate direction of the body. Smears tend to thin out along the trajectory - when the person first touches something the blood is thicker.


It is easy to simulate falling blood - you can do your own tests in the kitchen with a liquid that is similar to blood.


One important point about blood which is easy to forget is that if blood falls in one area, it probably falls in another too. So one should not entirely trust the police account of where blood was found at the scene.