Bloodstain Analysis & Patterns

Which item best describes the main safety hazard at a crime scene involving blood evidence?

• Sharp objects on the floor

• Electrical shock from equipment

• Exposure to bloodborne pathogens

• Slippery floors only

Which personal protective equipment (PPE) is most important to reduce risk when handling blood evidence?

• Sunglasses

• Gloves and face protection

• Knee pads

• High-visibility vest

Passive blood patterns are primarily created by which two factors?

• Gravity and surface texture

• Wind and temperature

• Magnetism and air pressure

• Light and shadow

When a blood drop falls straight down at approximately 90 degrees onto a smooth glass or plexiglass surface, what pattern is most likely observed?

• A nearly circular stain with smooth edges

• An elongated stain with a tail

• A smear with multiple breaks

• A large irregular splash

How does a rougher textured tile typically affect a blood droplet that hits it at 90 degrees?

• It produces a perfect circle with crisp edges

• It creates a circular stain with scalloped or irregular edges

• It always forms an elongated teardrop

• It absorbs completely with no visible stain

What pattern is a blood droplet likely to form on wood with noticeable texture?

• A smooth-edged circle like on glass

• A stain with irregular, spiny edges and small offshoots

• No stain at all

• A perfectly square stain

Which statement best defines satellite blood?

• Tiny secondary droplets that separate from the main drop upon impact

• Dried flakes of blood that peel away

• Invisible trace blood found under UV light

• Blood that travels only by capillary action

A CSI observes small secondary droplets surrounding a central round stain on a rough surface. What is the most reasonable interpretation?

• The blood was wiped after deposition

• The drop struck at a shallow angle

• Satellite spatter formed due to surface texture on impact

• The stain came from high-velocity impact

Which statement best describes a contact stain in blood evidence?

• A stain formed when blood drips freely through air

• A pattern created when a bloody object touches a clean surface

• A fine mist produced by high-velocity impact

• A stain created only on fabric surfaces

A repeating transfer pattern from the bottom of a shoe or tire can help investigators determine which of the following?

• How high the blood source was above the floor

• What direction the criminal left the scene

• Whether the victim had a preexisting injury

• The exact time the crime occurred