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What cops should know about processing void blood patterns

When assessing void blood patterns, investigators must try to determine the missing object, how it was involved and where it is now located


Often a missing object had a significant role in the event and has been possibly taken for concealment by the perpetrator.


Article updated on October 6, 2017.

When it comes to crime scenes and blood, numerous factors must be taken into careful consideration. Void patterns in particular require more detail in order to recreate the events of the crime scene. These patterns may be difficult to solve, but can add an ample amount of information to the story.

Void patterns and shapes have an absence of blood in the form of an object. The void is caused when the object has been removed from a pool of blood. Once the object is lifted, the shape is left behind.

When assessing void blood patterns, an investigator must try to determine:

  • What that missing object was;
  • How it was involved in the scene;
  • Where the object is now located.

This can prove challenging, as often the missing object had a significant role in the event and has been possibly taken for concealment by the perpetrator.

Documenting and Identifying

The first step is to photograph and measure the void pattern. Once dimensions are documented, the search for the object can begin. Though void patterns may be the cause of discouragement, they can also provide a solid piece of the crime scene puzzle.

“Voids tell investigators many things, first and foremost, that an item has been removed from the crime scene,” Sergeant Wade Proctor of the Ruidoso Police Department said. “That points to tampering of the crime scene.”

One fairly recent way to determine void blood patterns is by using the Void Pattern Shadow Matching method. This method has proven to be easy to accomplish and accurate. It is an effective way to figure out the dimensions of the object that is missing from the scene.

In order to get an effective “read,” you need is an LED flashlight and a tape measure. By casting the light onto the area where there is an absence of blood, a shadow will appear that may be measured. Once the measurements are complete, the investigator will have a better idea of what that missing object may have been.

“Void Pattern Shadow Matching can quickly help to determine pattern origins as well,” Proctor said.

When taking an in-depth look at void patterns, there are a few things investigators should note to have a better insight on the scene and situation.

“Look for shape, directionality of the void and shadowing,” Proctor said.

Hilary Rodela has extensive law enforcement and forensic training. She has been a professional writer for several years with a focus on public safety protocol, products and technology.