Ballistic Trajectory Lab and Notes
Crime Scene A: a shot was fired at the white vehicle parked across from the target store. The car is parked 75 ft from the store. A shot was believed to have been fired from the roof of the store. The store is 40 ft tall. Is it possible for the shot to come from the roof of the building? Explain your answer.
Crime Scene B: A 5. 5 ft man was walking in downtown Austin. The man is shot in the knee while heading toward the frost building. The man was 85 ft from the building. What floor was the shot most likely fired from. Assume each floor is 12 ft tall.
Crime Scene C: The UT Tower is 307 ft tall. A man walking down on the west mall is 365 ft away from the building. A shot was fired at the man at the angle given. Is it possible for this shot to come from the top of the tower? Why?
Crime Scene D: A rally is being held on the steps of the capitol building. Shots were fired from a building 267 ft away at the given angle hitting a tree 12 ft high. What floor should the police look for evidence on?
Types of Pattern Evidence for Identification and Comparison (Individualization Patterns) � Pattern evidence is generally created by the contact of two surfaces (persons, vehicles, or objects). Result in the formation of: ◦ Impressions ◦ Imprints ◦ Markings � Contact types: ◦ Static (stationary) ◦ Dynamic (moving) � Impression types: ◦ Two dimensional or three dimensional
Examples of Individualization Patterns Individualization patterns: � Individualization patterns are those which have the potential to be associated with an item or person responsible for it ◦ ◦ ◦ Fingerprints Palm prints Footprints Handwriting Toolmarks
Internal Ballistics � Conducted by the forensic firearms examiner at the crime lab. � Involves function and operation of the weapon, association of weapon, bullets and casings. � Often involves evaluation of ejection patterns and gun shot residue range determinations.
Terminal Ballistics � Conducted by the forensic pathologist. � Involves defining the path of a bullet through the body, the associated damage and differentiating entry from exit wounds. � Also includes issues of range determinations.
External Ballistics � Conducted by the crime scene analyst most often, may involve the firearms examiner. � Involves defining the path of a bullet through the scene by evaluating various scenes aspects, such as penetrations and perforations, casings and known positions of the victim or shooter. � Ultimately it defines possible and impossible scenarios for bullet trajectories.
Trajectory Kits � Primary concern of external ballistics is evaluating bullet defects. � Trajectory kits are used to do this, they include: ◦ ◦ trajectory rods. centering guides. angle finders. in some cases lasers.
Utilizing a Trajectory Kit � Verify the defect is a bullet hole. � This is done based on: ◦ visual examination. ◦ presence of bullets or remnants. ◦ chemical presence of lead or copper.
Utilizing a Trajectory Kit … continued � Insert the rod into a perforating defect. � Use centering guides to level the rod in the defect. � Lack of centering guides can affect the angle significantly.
Utilizing a Trajectory Kit … continued � Centering guides are used on both sides of the perforation. � Guides are not forced into the defect and are held in place by small rubber grommets.
Utilizing a Trajectory Kit … continued � Angle finder used to document the angle of the trajectory. � Documentation includes identifying the exact position of defects. � Rods can be extended several feet without sagging.