1. First of the Day….

2. What gets wetter and wetter the more it dries?
A towel

4. The “Luminol” Lab

7. There's a lot of unbelievable technology in shows like CSI -- computers that can zoom in and "enhance" a tiny section of a video frame; machines that can isolate a particular background voice from a muffled recording in a matter of seconds. Most of this is fiction, fabricated by screenwriters. But one tool, a special chemical that reveals invisible blood traces, is real…

8. A strange compound, commonly known as Luminol, can reveal hidden blood at crime scenes. This chemical is extremely useful, but it does have drawbacks and limitations.

9. As Edmond Locard said - a trace always remains when two objects or people come in contact, especially in violent crimes. A murderer can dispose of the victim's body and mop up the pools of blood, but without some heavy-duty cleaning chemicals, some evidence will remain.

10. Tiny particles of blood will cling unseen to the naked eye to most surfaces for years. Luminol reveals this trace evidence as a light-producing chemical reaction between several chemicals and hemoglobin, an oxygen-carrying protein in the blood.

11. The molecules “break” and their atoms rearrange themselves in such a way that the reactants (the original molecules) have more energy than the products (the resulting molecules).

12. These new molecules emit the energy in the form of visible light photons. This process, known as chemiluminescence, is the same phenomenon that makes fireflies and light sticks glow.

13. The "central" chemical in this reaction luminol (C8H7O3N3), is a powdery compound made up of nitrogen, hydrogen, oxygen and carbon. Criminalists mix the luminol powder with a liquid containing hydrogen peroxide (H2O2), a hydroxide (OH-) and other chemicals, and pour the liquid into a spray bottle.

14. hydrogen peroxide and the luminol are the principal players in the chemical reaction, but in order to produce a strong glow, they need a catalyst to accelerate the process. The mixture is actually detecting the presence of such a catalyst, in this case the iron in hemoglobin

15. To perform a luminol test, criminalists simply spray the mixture wherever they think blood might be.
If hemoglobin and the luminol mixture come in contact, the iron in the hemoglobin accelerates a reaction between the hydrogen peroxide and the luminol.
In this oxidation reaction, the luminol loses nitrogen and hydrogen atoms and gains oxygen atoms, resulting in a compound called 3-aminophthalate.

16. The reaction leaves the 3-aminophthalate in an energized state -- the electrons in the oxygen atoms are boosted to higher orbitals. The electrons quickly fall back to a lower energy level, emitting the extra energy as a light photon (With iron accelerating the process, the light is bright enough to see in a dark room.

17. Investigators may use other chemiluminescent chemicals, such as fluorescein or Bluestar, instead of luminol. These chemicals work the same basic way.

18. If luminol reveals apparent blood traces, investigators photograph or videotape the crime scene to record the pattern .
luminol only shows investigators that there might be blood in an area, since other substances, including household bleach, can also cause the luminol to glow.

19. Experienced investigators can make a reliable identification based on how quickly the reaction occurs. BUT they still need to run other tests to verify that it is really human blood such as the Kastle-Meyer Test

20. Luminol alone doesn't solve a murder case
Luminol alone doesn't solve a murder case. It's one step in the investigative process. But it can reveal essential information that gets a stalled investigation going again. Hidden blood spatter patterns can help investigators locate the point of attack and even what sort of weapon was used (a bullet makes blood splatter very differently than a knife does).

21. Luminol often leads investigators to more evidence if it detects trace amounts of blood on a carpet, investigators may pull up the carpet and discover a lot of visible blood on the floorboards below.

22. One problem with luminol is that the chemical reaction can destroy other evidence (like DNA) in the crime scene. For this reason, investigators only use luminol after exploring a lot of other options. However as on some TV shows, the police don't walk into a crime scene and start spraying luminol on every visible surface.

24. BLUESTAR® FORENSIC latent bloodstains reagent
A new reagent which reveals blood stains that have been washed out, wiped off or which are invisible to the naked eye. This product is intended for crime investigators.
Based upon chemiluminescence, its unique formula qualifies it as the most effective blood revealer available on the market, for crime scene as well as forensic lab use.
does not alter the DNA of the revealed
blood which allows for its subsequent
genotyping. It is also compatible with
ABO typing. Furthermore, it is safer and
easier to prepare and use.

27. Kastle Meyer Presumptive Test

28. Kastle Meyer Presumptive Test for Blood Kit : A chemical based presumptive blood test used a either at crime scenes or in a laboratory environment.

29. This is not a pregnancy test…A single blue line means the testing liquid is working fine but no human blood has been detected, two blue lines mean the test has detected human blood.  It is the Precipitin Test

30. blood spatter determination…
Is there Invisible blood? Luminol or Bluestar
Is it really blood? Kastle-Meyer
3. OK… we’ve got blood…is it human? Precipitin
(Disadvantage of Luminol destroys DNA
Bluestar does not)

31. Principle Human hemoglobin (hHb) in the sample
reacts with a reagent consisting of blue colored particles and monoclonal anti-human Hb antibodies.
The immunocomplex migrates to the test zone where it is captured by an immobilized second antibody directed against hHb forming a blue test line to indicate a positive result.
Unreacted reagents migrate further and are bound in a 2nd line by immobilized anti-mouse lgC antibodies. This control line indicates proper function and correct handling of the test.
The test detects whole blood up to a dilution of 1 : 1,000,000. As little as 500 red cells are required for a positive result.

32.
Kastle-Meyer

33. Blood platlets can be seen on fibers of fabric

34. Blood stains

37. Semen stain

38. The “Luminol” Lab