Luminol – The Search for Blood.

28 September 2010

Chemoluminescence with Luminol

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The luminol chemiluminescence reaction is responsible for the glow of lightsticks. The reaction is used by criminalists to detect traces of blood at crime scenes. In this test, luminol powder (C8H7O3N3) is mixed with hydrogen peroxide (H2O2) and a hydroxide (e.g., KOH) in a spray bottle. The luminol solution is sprayed where blood might be found. The iron from the hemoglobin in the blood serves as a catalyst for the chemiluminescence reaction that causes luminol to glow, so a blue glow is produced when the solution is sprayed where there is blood. Only a tiny amount of iron is required to catalyze the reaction. The blue glow lasts for about 30 seconds before it fades, which is enough time to take photographs of the areas so they can be investigated more thoroughly. Here’s how you can detect blood yourself or demonstrate how to do it:

Luminol Materials

  • luminol stock solution (2 g luminol + 15 g potassium hydroxide + 250 mL water)
  • 3% hydrogen peroxide in water (common over-the-counter concentration)
  • potassium ferricyanide or a sterile blood lancet and sterile alcohol pad

Performing the Test or Demonstration

  • In a clear test tube or cup, mix 10 ml of the luminol solution and 10 ml of the peroxide solution.
  • You can activate the glow either by adding ~0.1 g of potassium ferricyanide to the solution or with a drop of blood. The blood must be on the alcohol pad. The forensic test is for dried or latent blood, so the reaction between the alcohol and fresh blood is necessary.

Notes About the Luminol Test

  • In addition to iron and iron compounds, other substances can catalyze the luminol reaction. Copper and its compounds, horseradish, and bleach also cause the solution to glow. So, you could substitute any of these materials for the drop of blood or potassium ferricyanide in the demonstration. Similarly, the presence of these chemicals at a crime scene affects testing for blood. If a crime scene was washed in bleach, for example, the whole area would glow when sprayed with luminol, making it necessary to use a different test to find traces of blood.
  • If you are doing the reaction as a chemiluminescence demonstration, you can kick the display up a notch by dissolving the potassium ferricyanide in the peroxide solution and using a fractionating column or glass spiral to react the solutions rather than a test tube. You could pour a small amount of fluorescein in the bottom of a flask, pour the potassium ferricyanide solution through the spiral into the flask, and (in a darkened room) finish by adding the luminol solution. The spiral will glow blue as it passes through the column, but the glow will change to bright green once the luminol touches the fluorescein in the flask.
  • Don’t drink the luminol solution. Don’t get it on your skin or in your eyes. If you prepare a spray bottle of luminol solution to check for traces of blood, keep in mind the solution might be damaging to some surfaces. That’s not a big factor at a crime scene, but it’s something to keep in mind at home or in class. Don’t spray upholstery or clothing or people.
  • I am told you can use much less luminol (~50 mg) and still achieve enough luminescence for a demonstration or for crime work.

How the Test Works

The iron in the hemoglobin found in blood catalyzes an oxidation reaction in which the luminol gains oxygen atoms while losing nitrogen and hydrogen. This produces a compound called 3-aminophthalate. The electrons in the 3-aminophthalate are in an excited state. Blue light is emitted as energy is released when the electrons return to the ground state.

Luminol is only a tool and will give the Law Enforcement agency enough evidence to satisfy further investigations.

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He has the answers in his hands…

16 September 2010

Fingerprint detail on male finger.

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Many people do not realise what evidence you can get from friction ridge details on hands and as such I decided to compile a short guide to chemical processes.

I will not tell you how to carry out those processes here because a lot can be dangerous and to produce the evidence in court you would need to be certified and suitably qualified.

The first thing you do need is a working knowledge of fingerprints and the minute that make up the ridges.

As you can see there are many areas of the fingerprint that are important and everyone has different ones.

No two fingers are ever the same meaning the results of a fingerprint match are conclusive.

But it’s not only the fingerprints that contain ridges, other areas of the body carry them as well.  The palms for instance and very valuable in the hunt for criminals, that’s why  it is very important for the Police to maintain an active database of not only fingerprints, but palm prints as well.

Many countries are now taking palm prints every time they take fingerprints due to the ability of their comparison experts to identify a very very small area of ridge detail.

As you can guess, none of this is like the TV shows, CSI: MIAMI or CSI: New York. they are dramatic and nothing like real life. Although they do use a number of the products real life investigators use but the timings are completely shot to bits.

As is the fact that a Crime Scene Technician is able to be first on the scene, gun totting, and blues and twos everywhere. If only!!!

Once you have found a piece of evidence you will need to decide what processes you are going to carry out on it.

Now there are destructive and non destructive processes and you must always carry out the non destructive processes first. These can be completed using powders, chemicals or other processes involving equipment such as the ESDA from Foster & Freemen Ltd in the UK.

Once you have decided what processes you are going to use, ensure you have photographed your evidence. I recently worked in an organisation where the boss said NOT to photograph all the items before processing. Unfortunately if you are working on evidence that has specific markings like a letter or receipt, that can be obliterated during the processing.

YOU MUST ensure the evidence is photographed prior to processing. This can also be used to indicate to the court what state the evidence was in when it reached the lab.

Of curse should the unimaginable happen and that piece of evidence was ever lost, you also have a record of what it was. Not best evidence no, but its a record.

Following your photography and subsequent searches with light sources and chemicals the evidence can be packaged and sent back to the investigating officer ready for his court dates.

It should not be disposed of even if it’s a vehicle or large item. If the item will spoil (like and apple for instance) then it should always be disposed off after photography.

After you have used your chemicals to recover your marks you then need to capture them and enter them onto the Automated Fingerprint Identification System (AFIS) which is housed in most Criminal Record Offices.

From there it can be searched against either a specific person who is held on file, a person who has supplied prints for that enquiry or against the database for a speculative search.

Should any of these be positive the check must be verified by a number of people before it is published and the person arrested.

Most of the time that is all there is to it but occasionally the experts don’t agree and outside verification must be sort.

If you need outside verification one company you can use is this one Complete Policing, Defence and Medical Solutions Ltd who are based in Trinidad & Tobago.

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Ohh some good news for once

2 September 2010 2 Comments

Skulls on a Beach: "Currents carry many d...

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As this chapter in our lives comes to a close we must look for new horizons.

I have just seen a friend who is in authority here in my present organisation. On telling him this was more than likely my last night shift he asked on your or the organisations request? I replied the organisations and to be specific the Prats!

Well if looks could kill! That man was not even there with us but he must have felt the back of his neck go red !

I would love to see his face the next time he is in the Executive meetings. Oh to be a fly on the wall LMAO

Anyway , I explained what I was going to do next at the Officer, whom I have worked alongside for the last four years and we have a mutual respect, stated he would be happy for me to call on him and explain my business in more detail if it can save this organisation money! And as they are not flying people back and forth to the UK it will!

Which is just as well because I have just read this:

GIA announces the release of a comprehensive U.S. report on the Forensic Technologies and Services market. The U.S. market for Forensic Technologies and Services is projected to register $20.52 billion in annual revenue by 2015. Surging crime rates, particularly cases related to cyber crime, rising number of terrorist attacks, and stronger role of forensic sciences in bringing suspects to the book, are creating the need for increased adoption of forensic technologies and services. An increasingly security conscious society, dramatic changes in national security, and technology innovations are also expected to drive the U.S. market for forensic technologies and services in the next few years. Fast growing popularity of Biometrics/Fingerprinting and DNA analysis in legal investigations too augurs well for this market.

Forensic evidence, as gleaned from the collection of physical evidence from crime scenes, interpretation of laboratory findings, and presentation of the same in judicial proceedings, plays a pivotal role in criminal investigations. Given its potential to nail down the guilty and acquit the innocent, the social impact of forensics is huge. Forensic technologies have achieved new milestones over the last few decades. Advancements in technologies related to forensics, such as improved extraction of fingerprints from metals as in fragments and gun cartridges, portable use of color chemistry in identification of biological and chemical weapons, DNA-profiling techniques, and sensing technologies, which are aimed at improving detection of explosives and drugs at various security checkpoints, among others, have all played their part in increasing the market prospects for forensic technologies and services over the years.

Governed by rising crime rate, the demand for a full suite of forensic services, including collection, preservation, processing, and scientific testing and analysis of gleaned evidence, is rapidly on the rise in the U.S. Increase in gun violence, and growing instances of cyber crimes, and terrorist bombing across the nation are key factors driving growth in the U.S. forensic technologies and services market. While increasing gun violence is triggering a robust demand for forensic ballistics intelligence, including toolmark analysis, rise in cyber crimes is creating the need for increased adoption of computer forensics. With the Internet emerging into a ubiquitous vehicle for communication, and transfer and storage of sensitive data, there has been a surge in Internet related crimes, and abuse of corporate and government information assets. Hacking into secure networks for unauthorized access and use of data, and illegal data compromises, such as unauthorized use of credit/debit card information, result in significant business losses, which creates a special need for computer forensics technology, including tools for collecting and analyzing electronic data for presenting it as evidence in a court of law.

Another noteworthy growth driver for this market is the growing prominence of DNA testing. The heavily financed, researched, and scientifically validated field of DNA analysis has made DNA testing a de facto standard in forensic science. The increase in crime clearance rate has been directly attributed to the successful use of DNA technology. Forensic DNA diagnostics products and testing/analysis services are expected to benefit largely from the numerous government and federal level funding measures taken to upgrade the aging crime lab infrastructure. The government’s special focus on increasing the use of DNA technology for advancing the cause of justice will additionally drive gains in this space. DNA analysis, together with cyber/computer forensics and explosives investigation, has come to form an integral part of forensic science in the 21st century.

The current prolonged economic recession heightens the risk of commitment of felony, since poor economic health and higher levels of unemployment induces greater number of crimes such as those related to property, and drugs. The risk further rises if prolonged budgetary curbs are made on public safety by the government. Tough economic, financial, and business conditions have also resulted in an alarming rise in the number of corporate frauds being committed. Low employee morale is citied as a key factor triggering breach of trust and financial crimes committed by middle management. The scenario is helping ramp up demand for forensic fraud detection services. Given the growing magnitude of financial scams, forensic accounting services are especially witnessing higher demand and growth.

As stated by the new market research report on Forensic Technologies and Sciences, Forensic Databases, Forensic Consulting, and Computer Forensics, together make up the largest segment, having registered US$9.11 billion in annual revenues for the year 2009. Forensic consulting especially is a growing phenomenon in the U.S., given its role in easing the mounting workload in several understaffed domestic laboratories. The Biometrics/Fingerprinting market is the fastest growing segment, displaying a robust CAGR of more than 12% over the analysis period.

The report titled “Forensic Technologies & Services: A US Market Report” announced by Global Industry Analysts, Inc., provides a comprehensive review of current market trends, key growth drivers, issues and conceptual overview of crime labs in the country. The report also enumerates recent product introductions/innovations and strategic corporate initiatives in addition to providing profiles of key market participants. The report provides market estimates and projections for Forensic Technologies and Services in the U.S. in terms of annual revenue for the following segments: Forensic Databases, Forensic Consulting and Computer Forensics; Biometrics/Fingerprinting; DNA Testing; and others.

For more information, visithttp://www.strategyr.com/Forensic_Technologies_and_Services_Market_Repor…

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