CHRIS SCHAEFER, OMS II PRIYA NILESHWAR, OMS I NNAEMEKA DIRIBE, OMSI Blood Spatter Patterns Murder or Self Defense?

Types of Patterns

High Velocity

Medium Velocity

Low Velocity

How can we find out where the blood came from?

Pattern Analysis Select drops of blood with an easily identifiable shape Measure length and width of droplet

Pattern Analysis Divide width by length This gives you the sine of the angle at which the blood impacted the wall

Pattern Analysis Measure angle with protractor and attach a string next to the droplet at angle of impact Where all the strings come together gives location of source of blood

Which Drops are Good?

Good!

Which Drops are Good?

Bad!

Measure Length and Width

Divide Length by Width Width Length

Determining Angle This will give you a decimal number The actual formula (for those of you with a little bit of Trigonometry) is arcsin(number)=angle

Math?!? Say What?

Determining Angle We can just estimate with this table.1 = 6 degree angle.2 = 11 degree angle.3 = 17 degree angle.4 = 24 degree angle.5 = 30 degree angle.6 = 37 degree angle.7 = 45 degree angle.8 = 53 degree angle.9 = 64 degree angle 1 = 90 degree angle

Measure Angle and String

Area of Convergence

Case How can we know if a killing was due to self defense or murder?

Story Stewie states that he was defending himself against Brian who was coming after him with a knife. Both of them were standing when this happened. Stewie says he struck Brian in the head while he was still standing.

Evidence

Is he telling the truth?

High or Low Velocity ?

Good or Bad Pattern?

Good Pattern must have a tail. True/False?