Blood Splatter Analysis: Unraveling Clues in Crime Scenes

In the realm of forensic science, blood spatter analysis is a crucial investigative technique that helps investigators reconstruct crime scenes and uncover valuable evidence. This specialized field plays a significant role in solving crimes, providing critical insights into the dynamics of violent incidents, and aiding in the pursuit of justice. From homicides to accidents, blood spatter analysis is an invaluable tool that has revolutionized the way investigators approach crime scene investigations.

Understanding Blood Spatter

Blood spatter refers to the patterns created when blood is released into the environment, typically as a result of an injury or wound. The size, shape, distribution, and appearance of these bloodstains can offer valuable information about the nature of the incident. Different types of forces, such as impacts, gunshots, stabbings, or arterial spurts, can produce distinct blood spatter patterns, and skilled analysts can interpret these patterns to draw conclusions about the events that transpired.

Principles of Blood Spatter Analysis

Blood spatter analysis relies on several fundamental principles, including:

1. Impact Angle: The angle at which blood strikes a surface affects the shape and size of the resulting bloodstain. By analyzing the spatter's shape and dimensions, experts can determine the angle of impact and infer the position of the victim or the assailant at the time of the incident.

2. Point of Origin: Bloodstain patterns can be used to determine the location from which the blood originated. By tracing the trajectories of multiple blood spatters, investigators can identify the point of origin, providing valuable insights into the dynamics of the event.

3. Spatter Velocity: The force with which blood impacts a surface influences the spatter's size and shape. Higher velocities result in smaller droplets, while lower velocities produce larger stains. This information can help reconstruct the sequence of events and the relative positions of individuals involved in the incident.

4. Transfer and Contact Stains: Blood can be transferred from one surface to another when they come into contact. By analyzing contact and transfer stains, investigators can deduce actions taken by both the victim and the suspect during the crime.

5. Directionality: The shape of blood spatters often indicates the direction in which the blood traveled after the injury. This information can be used to recreate the sequence of events leading up to the crime.

6. Passive, Projected, and Impact Spatter: Different types of spatter, such as passive (dripping), projected (spurting), or impact (caused by external force), provide insights into the nature of the injuries and weapons involved.

Applications in Crime Scene Investigations

Blood spatter analysis finds applications in various criminal investigations, including homicides, assaults, suicides, and accidents. By meticulously studying the bloodstain patterns, investigators can corroborate or refute witness statements, establish timelines of events, identify potential murder weapons, and even provide critical evidence in court.

Challenges and Limitations

Despite its usefulness, blood spatter analysis has some limitations. It is essential to consider factors such as gravity, wind, and surface texture, which can influence the appearance of bloodstains. Additionally, the interpretation of blood spatter patterns is an intricate process that requires a highly skilled and experienced analyst.

Conclusion

Blood spatter analysis is an indispensable tool in modern crime scene investigations. By providing a scientific and objective approach to understanding bloodstain patterns, it allows investigators to unravel the mysteries surrounding violent incidents. From establishing the sequence of events to shedding light on the roles of individuals involved, blood spatter analysis serves as a crucial ally in the pursuit of truth and justice.

Public Safety Technology in the News

Tennessee Meth Task Force Adopts Mobile Narcotics Detection Solution
Government Technology, (08/28/2008)

Tennessee Meth Task Force (TMTF) agents now have a tool at their disposal that can provide near-instant detection and identification of narcotics and explosives in the field. The three MobileTrace units are capable of providing agents with reports in seconds that can then be submitted as evidence in court for drug-related prosecutions. The TMTF's previous tool for this type of work was a desktop device that limited mobility that was not capable of field detection. The unit's dual-mode ability detects narcotics and a wide array of explosives, and longer battery life provides agents with a tool that is effective, efficient, and ensures their safety.
www.govtech.com/gt/401898?topic=117680

TGen Find Promises Big Leap in Forensics
The Arizona Republic, (08/29/2008), Ken Alltucker

An "accidental discovery" by a team of researchers from Translational Genomics Research Institute and UCLA found that a technique used to identify disease triggers in a patient can also be used to identify individuals based on DNA samples from a busy crime scene. Using mixtures of DNA, the scientists were able to analyze the samples using microarrays, a high-powered automated technology to isolate an individual's DNA. The scientists concluded that the technology could isolate an individual's DNA even if the sample included 200 other DNA samples. This ability to isolate DNA samples from mixtures that large could help law enforcement with investigations of crime scenes such as a busy convenience store or a bank, where the samples often go unused because of the amount of DNA samples involved.
www.azcentral.com/arizonarepublic/news/articles/2008/08/29/20080829biz-dnaswab0829.html

police Using GPS. Units as Evidence in Crimes
The New York Times, (08/31/2008), Associated Press

The popularity of Global Positioning Systems (GPS) is helping authorities investigate crimes. Originally developed for use by military, GPS began showing up in the 1990s in consumer cars and trucks. Costs have dropped and the units have become more portable, which has made them more accessible. GPS has become a useful tool for the public, but now prosecutors and police are beginning to learn the full potential of these units for use as evidence. In 2005, a family was murdered in Chicago, and the suspect was convicted and sentenced to death this year based on data that was retrieved from the GPS unit in his SUV. The use of GPS can establish a defendant's whereabouts.
www.nytimes.com/2008/08/31/us/31gps.html?_r=1&ref=us&oref=slogin

Deputies' Cars to Get Digital Upgrade
The Arizona Republic, (09/04/2008), Yvonne Wingett and JJ Hensley

Maricopa County will be purchasing an upgraded communications system to speed sheriff's deputies' response to emergency calls. The new system will replace standard radios in patrol cars and provide deputies instant access to multiple databases prior to engaging suspects or responding to calls. It allows deputies to check for warrants and other information without radioing and waiting for dispatch to respond. Computerized equipment, similar to laptops, will initially cost the county about $2 million, with an annual maintenance cost of $850,000. At this point, it is unclear how this system will impact the department's self-imposed response time of 5 minutes or less on priority one calls, but the agency hopes is it will help the agency maintain that goal or come in under it.
www.azcentral.com/arizonarepublic/local/articles/2008/09/04/20080904MCSOresponse0904.html

City Uses Technology to Track Speeders
NBC4, (09/04/2008), Denise Yost

Columbus city officials will be deploying 10 smart speed trailers throughout the city to capture data relating to when and where speeding is occurring. City officials will then turn the data over to the city police to evaluate and use to decide where to deploy officers. Also, the city plans to implement a rotating schedule for placing the trailers, using information from the community through requests received on the city's 311 information line.
www.nbc4i.com/midwest/cmh/crime_watch.apx.-content-articles-CMH-2008-09-04-0019.html

New 911 Technology is Call of the Future
The Telegraph, (09/06/2008), Cynthia M. Ellis

At the National Emergency Numbers Association conference, Madison County 911 coordinator Bill Gamblin stated, "There is a generation of people who doesn't leave home with out their [cell] phone." This is the premise and driving force behind the creation and development of the Next Generation 911, or NG991, that is an updated 911 system that can use and be accessed in a wireless society. It would allow witnesses to a catastrophic or HAZMAT event to use their cell phones to provide video footage of the event, still images, or allow text messages describing the scene. It would also interact with automated vehicle systems that would alert the 911 center in response to an airbag deploy and provide 911 with the car driver's medical records. For the first responders, this system would then provide the chance for dispatchers to forward the footage and images to allow the responders a chance to understand and prepare for the scene prior to arrival.
www.thetelegraph.com/news/gamblin_17981___article.html/ng911_calls.html

DNA Testing Expands to Lesser Crimes
The Washington Post, (09/08/2008), Dan Morse

Advances in the processing of DNA samples from crime scenes have made it a tool not only to be used for crimes like rape and murder, but also for the less violent crimes like burglary, robbery, and drug dealing. An example of that is a 2002 Starbucks robbery case in Montgomery County, Maryland, where the suspect left behind a half-empty cup of coffee. No arrests were made in the case.. Then in 2007 the DNA sample was run against the state's database of felons and a there was a match. The suspect is on trial. Prosecutors hope the introduction of DNA sampling into these less violent crimes will speed the criminal justice process by leading to more guilty pleas. The director of Montgomery County's crime lab hopes that by spring his lab will be using robots to extract DNA samples. The robots and a new gene sequencing technology are hoped to increase DNA analysis by 30 percent and make it a more efficient tool for the less violent crimes.
www.washingtonpost.com/wp-dyn/content/article/2008/09/07/AR2008090702340.html?hpid=moreheadlines

A Way to Find Hidden Fingerprints
Technology Review, (09/04/2008), Brittany Sauser

Physical evidence is needed by investigators to tie a criminal to a crime and that physical evidence can be as small as a fingerprint. But sometimes that evidence can't be seen because it has been washed away or because of the violent nature of the crime. In an explosion or in the case of arson, the print can be removed. Now with the discovery by Forensic Scientist John Bond, those invisible prints can be found. The findings are that when metals such as copper or brass come into contact with the oils and chemicals that make up a fingerprint, the metals corrode slightly. The corroded spots can only be removed with abrasive cleaning. In order for this invisible print to become visible, investigators have to apply voltage to the metal and apply a metallic powder that adheres to the areas that have corroded. This technique can be used for things like shell casings or metal shrapnel from a bomb, but because of the small nature of these pieces of evidence, getting a reliable fi! ngerprint becomes an issue.
www.technologyreview.com/Infotech/21331/?a=f

New York City Enhances Technology for Crime Fighting
InformationWeek, (09/10/2008), K.C. Jones

New York City will now have the ability to accept photos or videos from citizens regarding quality of life complaints and reports of criminal activity. This comes after the New York Police Department last month announced it's ability to accept tips via text messages. The implementation of this sort of technology is a fulfillment of Mayor Michael Bloomberg's State of the City promise. Callers can either contact 911 to report criminal activity or 311 for quality of life complaints. For criminal reports, detectives will follow up the original 911 call and explain how to provide the video or photographs to police. For quality of life complaints callers inform the dispatcher that they have photos or video to provide and receive instructions from the dispatcher or they are directed to the New York City homepage to upload their information. Bloomberg feels the new technology will bring the city up a level regarding fighting crime and making city government accountable for condit! ions in the city.
www.informationweek.com/news/personal_tech/cameras/showArticle.jhtml?articleID=210600911&subSection=All+Stories

police Probe Cell Phones to Thwart Criminals
San Francisco Chronicle, (09/08/2008), Tom Abate

Wireless technology available to would-be criminals dictates that the law enforcement community look in new places for evidence. For the San Francisco police that means adoption of new technology that extracts evidence from cell phones. San Francisco has acquired technology from multiple vendors that allows police to extract data such as text messages, contact lists, or images that the user may have thought were deleted from the phone's memory. The commercial version of these devices allows consumers to transfer data from one phone to the other in the event of a phone upgrade or change in service provider. For law enforcement, however, the technology allows extraction of data to help prevent corruption of evidence.
www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/09/07/BUPA12OC2V.DTL

Conversations with Cops

This week’s topic: Law Enforcement Driving Technology; Crime Scenes
Bruce Mather, Chief Technology Officer Lap Belt Cinch, Inc. will be discussing high speed driving technology during the first 15 minutes of the show. Kathie Jo Kadziauskas, AAA Crime Scene LLC, will be discussing the aftermath of crime scenes - everything from decomps to hoarding.

The Watering Hole
The Watering Hole is police slang for a location cops go off-duty to blow off steam and talk about work and life. Sometimes funny; sometimes serious; but, always interesting. During the first half-hour of the show, the host, a nationally recognized expert on law enforcement, interviews a subject matter expert on the topic. During the second half-hour the program is joined by two other cops who give a street-level perspective to the conversation.

Listen, call, join us at the Watering Hole.
http://www.blogtalkradio.com/LawEnforcement