Criminalistics is the application of various sciences to answer questions relating to the examination and comparison of biological, trace evidence and impression evidence such as fingerprint analysis, footwear and tire impressions and toolmark evidence as well as drug analysis, ballistics and firearm examination.

There are numerous chemical reagents available to enhance and locate the presence of blood deposits. I’ve listed some of the more common and effective chemicals:

Phenolphthalin (Kastel-Meyer).

This test is performed by rubbing a cotton swab that has been moistened in a saline solution on the suspected blood stain. A drop is added to the swab then a drop of hydrogen peroxide 3%. A positive reaction will turn swab PINK to RED within 15 seconds

Leucomalachite Green (LMG). This t

est is performed the same way as above. A positive reaction is indicated by a GREENISH-BLUE color that will appear almost immediately.

Luminal. This reagent is sprayed onto the object to be checked. However, it must be viewed in total darkness. In positive reaction will luminesce VIOLET within 5 seconds.

Ortho-Tolidine. This test is performed by rubbing a cotton swab that has been moistened in a saline solution on the suspected blood stain. A drop is added to the swab then a drop of hydrogen peroxide 3%. A positive reaction is indicated by an intense BLUE color.

Tetra-Methyl Benzidine (TMB).

Another in a series of presumptive tests that is specific for BLOOD. TMB is an enhancement reagent. The TETRA-METHYL BENZIDINE reacts with the HEME in the blood.

Spray the surface lightly 2 to 3 times about 10 inches away from the surface. The Bloody Imprint Pattern should turn a Greenish-Blue. Over spray may give a very Dark BLUE pattern and mask ridge patterns.

Hemaglow. This is a protein reactant, which does not ordinarily react with household cleaners like Luminol does. Hemaglow also glows brighter and can be photographed with a flat plane camera.

Amazing Advances in Forensic Science Part 2: Advances in CriminalisticsArticle by Vernon J. Geberth, M.S., M.P.S. Homicide and Forensic Consultant

©2010 Vernon J. Geberth, Practical Homicide Investigation Reprint: Law and Order, Vol. 58, No. 9, September, 2010, Article Expanded

Leucocrystal Violet (LCV). This is a

relatively new positive blood identifier that turns permanent VIOLET when in contact with blood. Leucocrystal violet can be testified to in court as a blood identifier at the scene without further testing to identify the stain as blood.

Fluorescein The chemical mixture of fluorescein causes a catalytic reaction to occur between the hemoglobin in blood and oxygen. This produces a luminescent stain, which will luminesce in the dark when excited ALS. Major advantage is that it will continue to luminesce for hours under UV or ALS after the initial application, and without additional applications of the reagent. Forensic Toxicology

For centuries, poisoning had been a popular method of murder.  The reason that poison is used is because it mimics common medical diseases, leading physicians to believe a victim died of natural causes. Arsenic was very popular as a poison as well as other heavy metals such as thallium. Many cases of arsenic poisoning had been attributed to gastric conditions in the 19th century. Metal based poisons soon became very detectible with standard toxicology tests.

Plant based toxins began to make their appearance. In fact, any natural substance in the right dose can be poisonous. Determining whether or not a poison was used requires a toxicological examination. 

Scientists and researchers continue to improve and discover new means of separating, analyzing, and identifying chemical substances. Techniques are becoming more specialized, and technologies are being combined to create ever more sensitive and sophisticated tests.

Two increasingly important approaches to chemical detection and identification are gas chromatography, a method of separating substances, and mass spectrometry, a method of measuring the mass of molecules. These techniques allow investigators to identify with reasonable certainty—admissible in a court of law—minute amounts of toxic substances found in the bodies of victims or in trace evidence collected at crime scenes.

Image Enhancement Methodology

Advances in image-enhancement technology are helping police visualize evidence, such as imprints and impressions. Imprints are patterns left on hard surfaces. Impressions are three-dimensional patterns or indentations made in a softer medium such as mud, sand or snow.

Fingerprints

Technology also has improved in the ability to detect latent fingerprints, which are among the most valuable types of physical evidence in criminal investigations. Fingerprints are accepted by the courts as good evidence for personal identification. In addition to dusting with powder for detecting and visualizing latent prints at a crime scene, there are techniques using chemicals such as cyanoacrylate (“superglue”), iodine fuming, ninhydrin reagents, silver nitrate and fluorescent reagents as well. Furthermore, there have been some remarkable results in developing latent prints by use of the laser. These techniques have expanded the capabilities of investigators.

Utilization of Automated Fingerprint Identification Systems (AFIS) has significantly advanced the ability of law enforcement to identify and apprehend criminals whose prints are in the various databases. Several AFIS technologies are in use across the United States, which can

be problematic because the investigator may have to submit a questioned latent to more than one AFIS database. However, AFIS has revolutionized the manner in which police departments search latent prints for matches. Entire databases containing hundreds of thousands of fingerprints can be searched within minutes. Latent prints recovered from a crime scene can be computer matched to a criminal fingerprint database. The success of these systems is due to the large databases maintained by a number of state law enforcement agencies as well as the military and other government agencies, which maintain fingerprint databases on all personnel and employees.

New Advance In “Bullet Fingerprinting” Technique.

“Bullet fingerprinting” technology developed at the University of Leicester in England may revolutionize how authorities obtain fingerprints off bullets or metal casings including bombs. The technique involves studying the chemical and physical interactions occurring between the metal and the fingerprint sweat deposit. Using advanced surface imaging techniques, such as an atomic force microscope, nanoscale observations of fingerprinted brass samples can identify optimum conditions to promote the natural enhancement of the fingerprint, vastly improving their recovery rate. It has also proven that components of the sweat deposit survive washing and wiping of the surface. As explained by Researcher Alex Goddard, "Once a finger has touched the metal surface, a residue remains behind, this starts to react with the metal and an image of the fingerprint can be developed by use of elevated temperature and humidity, with the resultant image becoming a permanent feature on the surface of the metal." Alex Goddard recently presented his findings at the University of Leicester's Postgraduate Research Festival.

Currently, fingerprint recovery from bullets is very low; less than 1 percent. This new technique uses a natural process and even if it only leads to small increase in success rate, then that would be significant. Previous recovery methods include applying powder to the material which can actually damage the evidence. This new technique promotes a naturally occurring process which does not involve adding anything to, or damaging, the evidence. Instead, it employs heat and humidity to promote the enhancement of the fingerprint image, there are also indications that it could be used after other techniques have failed, perhaps as a last resort.

Forensic Lasers and Alternate Light Sources

Forensic Lasers produce an extremely high-energy beam of light that is capable of causing fluorescence in certain materials. The fluorescent effect is usually viewed through goggles or lenses. They are quite expensive and require accessory cooling systems. Forensic Lasers, because of their size are usually confined to laboratories.

The Alternate Light Source (ALS) is more portable and less expensive today. Initially,

The original units were so heavy and cumbersome they had to be wheeled into the crime scene on a hand truck. Today, the ALS units are hand held with twice the amount of power. The Alternate Light Source (ALS) is a high intensity white-light source which has multiple filters that provides several wavelengths of visible light for examining the scene. In addition, you can use infrared, polarized, or oblique lighting. ALS units can detect microscopic trace evidence, such as hairs.

Both Lasers and Alternate Light Source (ALS) units detect body fluid stains, fibers and various materials that contain chemical substances capable of fluorescence. These units are also useful in locating fingerprints when fluorescent fingerprint powder is applied. Most of the

wavelengths in an ALS are in the visible range of the spectrum. An Ultraviolet Source can be built into an Alternate Light Source unit. The usefulness of UV depends on the fluorescence capability of the trace evidence. Some obstacles are, laundry detergents, etc.

Hair

Species, race and location of growth can be determined from hair as well as cosmetic information (dyed, bleached, straightened, etc.) In addition, DNA analysis can link hair to a specific source using either STR/DNA and/or mtDNA. Furthermore hair retains toxins, so the hairs can be analyzed for drug use and/or drug history.

Fibers

Fibers are an important part of trace evidence used to track suspects. Forensic fiber analysis is a critical element in crime scene investigation. Fibers, like hairs, may be transferred between the victim and perpetrator, and provide the investigator with an additional piece of class evidence which can be subjected to microscopic and microchemical testing. Advances in microscopic and microchemical testing has enabled investigators to origin fibers as follows: Vegetable (cotton and hemp), Animal (wool and mink), Mineral (glass wool and asbestos) and or Synthetic (nylon and orlon).

Forensic Examination of Firearms and Ballistics

In the 1980’s all we had to check ballistics nationwide was the “Drugfire” program administered by the FBI. It had been initiated during the drug wars of the 1980’s to track murders and killer using the same gun. Today, we have The National Integrated Ballistic Information Network (N.I.B.I.N.) presently every gunshot case sent to the FBI or ATF is on file. Thousands of bullets that have been read by laser and coded for computer storage are on file using the technology provided by Forensic Technology, Inc. called IBIS.

The Integrated Ballistic Identification System (IBIS) developed by Forensic Technology, Inc. is an image analysis system for acquiring, storing and analyzing the images of bullets and cartridge cases. IBIS® is Forensic Technology’s cornerstone product and has proven to be one of the impressive advances in forensic science and criminalistics. The System is comprised of two modules: BULLETPROOF® for bullets and BRASSCATCHER® for cartridge cases

The system captures video images of bullet striations and the markings left on cartridge cases, which produce an electronic “signature” stored in a database. Networking hardware and software allow transfers and comparisons of forensic evidence from different cities and countries.

Gunshot Residue Testing

The most effective gunshot residue testing (GSR) in the past was done with the scanning electronic microscope and atomic absorption with SEM-EDX capability. Today ASPEX has become the world leader in Gun Shot residue testing. When a weapon is fired or discharged, it produces a residue from the combustion of the primer and powder in the shell cartridge.

Residue may adhere to the skin or clothing of the person who discharged the firearm, or on other people and objects in close proximity at the scene. The major primer elements are lead

(Pb), barium (Ba), or antimony (Sb). Gunshot residue (GSR) is normally a combination of gunpowder and lead residues. As lead-free primers are becoming increasingly common (lead is replaced by aluminum and strontium), new methods are required to handle GSR analysis.

Traditional approaches would no longer be useful, but ASPEX GSR can be configured to detect, classify and report on new types of ammunition. The Aspex GSR Analyzer is a dedicated system capable of performing high through put analysis of GSR samples. The PerceptionTM software platform seamlessly integrates the SEM and the EDS components for a fast and accurate analysis. We have certainly come a long way from Trace Metal Detection or Neutron Activation Analysis tests of years ago, which gave mixed results.

Cell Phone Technology

Thirty years ago we didn’t have cell phones like today. The first generation of cell phones began in 1973 with a Motorola hand-held analogue model. The first commercial cell phone service began in 1983 and the devices were basically “Bag Phones”. The first modern network technology began in the 1990’s with the introduction of the Motorola StarTac flip phone in 1996. Wireless technology for cell phones has existed for a long time, but it was only very recently that cell phones themselves became practical and popular. In fact, wireless technology has made huge advancements in the last five years, and it continues to do so. Cell phones are quickly becoming one of the most widely used pieces of technology in the world.

Initially cell phones were only used to send and receive calls but with a fast influx of new technology, they are a lot more that just a phone. Everyday a new cell phone enters the market with a new amazing feature. First it was games for your phone, next came the digital camera and then after that the video camera and these are just a few forms of technology to make their way onto today's cell phones. What used to be a tool for making and receiving calls now has the ability to do much more.

From an investigative standpoint, the cell phone has become a crucial source of information. Cell Phone Technology is giving detectives leads in cases that they may not have had before. Today the newer phones are being equipped with the global-positioning technology that pinpoints the user’s location within dozens of yards.

As the hand-held devices grow smarter and hold more and various kinds of data, they become something like highly mobile closets of information such as contacts, images and text conversations. Police can use the cell records to track the owner’s movements, which can establish or refute an alibi. It’s a valuable tool in law enforcement’s toolbox as the investigators ask, "Who do you know? Who have you been talking to? And what are the conversations?"

The science of recovering digital evidence from mobile phones, using forensically sound conditions and accepted methods, is called mobile phone forensics. In general, forensic science is the application of scientific principles for legal, investigative, and public policy purposes. Digital forensic science refers to the preservation, acquisition, examination, analysis, and reporting of electronic data collected and stored on computer and network systems and on many digital devices. Guidelines on Cell Phone Forensics: Recommendations of the National Institute of Standards and Technology was issued in May 2007 as NIST Special Publication (SP) 800-101. Written by Wayne Jansen.

Estimating Time of Death – Scientific Breakthroughs

The Molecules of Death The bacterial putrefaction of the human body is a progressive breakdown of complex biological compounds into smaller and simpler ones. Scientists can now make determinations of T.O.D. based on microbial digestion of the body’s proteins, which produce chemical compounds.

Scientists have isolated 30 compounds specifically linked to decomposition in buried bodies.

Researchers from the University of Tennessee have identified these compounds which are uniquely human. This breakthrough will immediately be useful in creating chemicals to train cadaver dogs.

The future of forensics in recognizing the 30 Human Compounds of Decomposition will be the development of hand-held devices, which will in draw the air with a pump to concentrate and analyze samples, which will provide an estimated Time of Death.

New Technique Developed To Date Forensic Death Based On Corpse Microorganisms

In a similar study a group of scientists of the University of Granada has developed a new technique of forensic dating based on thermo-microbiology, which will allow technicians to determine more accurately the time of a death which has not occurred under controlled natural conditions or as a consequence of a crime.

This new system, of great interest in the field of criminology, establishes correspondences between the parameters of micro-organic growth on cadaverous remains and dates the time of death of such remains, as well as their relation with their temperature.

They have used new thermographical and weather measurement tools and they have applied traditional microbiological methods with a new approach. The purpose was to make easier the analysis of the stages of cadaverous decomposition and putrefaction, connecting them with the model of growth/death of the micro-organisms, responsible for the post-mortem alterations. The aim of this work, in short, is to establish a microbiological indicator to determine the Time of Death.

Conclusion

This extensive article examined some of the advances of forensic science over the last thirty years in connection with the application of science to the investigative process. It was intended to familiarize investigators with the potential possibilities and capabilities, which can be applied to their criminal investigations.

Vernon J. Geberth, M.S., M.P.S. is the author of the Practical Homicide Investigation: Tactics, Procedures, and Forensic Techniques, FOURTH EDITION and Sex-Related Homicide and Death Investigation: Practical and Clinical Perspectives SECOND EDITION CRC Press, LLC. These materials are excerpted with Geberth's permission and are protected under U.S. Copyright Laws.