An interesting topic Sherlock faces at almost every crimes scene, blood. How does he figure out the direction of the bullet and what weapon was used? What is his method and how do I personally achieve this skill? The skill involves using Sherlock's method of deduction and understanding the small details that reveals the questions to be elementary. A bloody crime scene is like a jumbled math problem.

Blood can be examined by three major factors:

shape

projection angle

velocity

Shape

The shape of blood and the diameter of the droplet has a direct correlation to the distance in which it fell. The higher the droplet, the bigger the diameter. This logic can determine height of victim, origin of wound, and placement of victim. The amount of blood present at a crime scene can also help determine details that help the consulting detective.

The average adult has 4.5 - 5 liters of blood in their body. If a crime scene has a pool of blood and a trail of blood in the opposite direction, then it is safe to deduce the body was moved. This can aide in understanding details about the crime committed and gaining a better understanding of the murderer.

Projection Angle

Projection angle is based upon ArcSin (width divided by length of the the blood stain). The greater the difference between the width and length, the steeper the angle. A blood drop that a perfect, round, diameter would have an angle of 90 degrees, but a droplet projected from a bullet, would have a much steeper angle.

This formula can be applied to all droplets and then this formula can began to paint a picture of the origin of impact. This can be used to determine when the first blow was delivered and where the victim was at during the crime.

Velocity

Velocity determines the weapon used and crime committed. The type of velocity is determined by droplet

size and projection.

Three different types of velocity:

low

medium

high

The low velocity impact spatter is where the blood droplet falls because of gravity. An example of this is when you cut your finger and a blood droplet falls to the ground. These droplets are mainly 90 degrees.

A medium velocity impact spatter is from a blunt object or sharp hand held object. An example of this is someone swinging a hammer and striking someone. The blood droplets are presented in sharp angles and protrude in groups of surrounding droplets with similar tail projections.

A high velocity impact spatter are usually from a gun or heavy machinery (car). This can be seen from the cluster of tiny red dots that surround a crime scene.

Sherlock examines these crime scenes with a keen sense of detail and a combination of true deduction. Understanding how blood spatter analyst conduct forensics, can offer a new appreciation to the consulting detective's methods. Sherlock examines crime scenes with the art of detail and a general knowledge of the blood projection. Blood spatters are just another puzzle that must be viewed with wonder and must be questioned profusely.