Blood pattern analysis (BPA) is an area of forensic science that is extremely important but extremely under-rated – people seem to have a misconception about how easy it is to “read” blood patterns (no doubt not helped by CSI!). To become proficient in blood pattern analysis requires more than just a few tests drips cast down a wall or onto paper. Understanding the variability in pattern (or lack of) created by direction, velocity, flow, depositional surface…. are crucial to correct interpretation of blood patterns. As with any other area of forensic science, specialised training is required plus considerable experience backed up with advice and peer-review. It’s not the sort of thing that can just be Googled for a quick answer.
Finally I have managed to find a good online resource that details how to record blood patterns: Documenting Bloodstain Patterns Through Roadmapping . It may sound ridiculous but you’d be amazed at how poorly blood patterns are recorded in casework. As the article states, “As the old adage goes, “a picture is worth a thousand words.” However, in the field of crime scene investigation this saying should be changed to “a properly taken picture is worth a thousand words.” Never is this more true than when documenting bloodstain patterns at a scene. Proper documentation of a crime scene, and bloodstains specifically, verifies the integrity of the scene and the evidence within it; provides quality presentations for subsequent courtroom testimony; and allows for outside analysis by other experts. The fundamental goal of documenting bloodstain patterns is to accurately depict the patterns as you found them.” One of the key indicators of a good crime scene examiner is the ability to record information from a crime scene so that it can be viewed at a later date by individuals who have not attended the crime scene so that they, in turn, will be able to understand what was present and, if necessary,re-interpret the patterns. Some people could learn from this….