Bianca Garcia Daniel Perez Maria Merino Sabina Vincevic Sara Glowacz

 Blood and other body fluids found at the scene of a crime may give important physical evidence in three ways;  Occurrence of a blood stain in a certain place, e.g. on a weapon may substantiate an account of a crime.  Shape, position, size or intensity of a bloodstain may support a particular sequence of events.  Blood typing analysis can be used to eliminate whole groups of people as suspects. It is thus obviously important to be able to identify a particular stain as blood or not, or maybe even to reveal "hidden" bloodstains on dark materials or where attempts have been made to wash the blood away.  Human blood contains a pigment called hemoglobin, which is used to transport oxygen around the body.  This pigment is used by a number of tests used to identify the presence of blood.

 One particular test that reveals the presence of blood is the Luminol Test.  In this test the bloodstains can be made to glow with a blue light due to the chemiluminescent reaction of the luminol reagent with the iron in the hemoglobin.  This test is sensitive enough to pick up minute traces of blood even when attempts have been made to wash away the incriminating evidence.

 The luminol chemiluminescence reaction is responsible for the glow of light sticks.  The reaction is used by criminalists to detect traces of blood at crime scenes.  In this reaction, 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.

 BLUESTAR® FORENSIC is a new reagent whose purpose is to reveal 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.  BLUESTAR® FORENSIC 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.

 Luminol allows for the detection of microscopic traces of blood.  Can detect blood traces that are many years old  Bluestar does not need complete darkness in order to be seen  Any area sprayed with luminol can be photographed providing permanent evidence from the crime scene

 Luminol can be used several days after the solution is made.  The luminol test does not destroy DNA  Luminol contains the same luminescence during a second application

 Other evidence at the crime scene can be destroyed by luminol’s chemical reaction.  Substances besides blood can also trigger luminol chemiluminescence.  Such as copper metal or bleach  Luminol can detect small traces of blood not neccessaroly part of the crime scene  Such as in urine or feces

 Although small traces of blood can be detected, luminol will further dilute the trace of blood  Luminol reacts to animal blood the same as it does to human blood.  Untrained officers may misuse the luminal which may possibly destroy evidence at a crime scene.

 The luminol test can be used at a scene where significant amount of blood is expected, but is not present.  Luminol testing should also be used if there are any signs of bleach on the floor or near the scene.  This is because many perpetrators use bleach to clean up the blood from the scene.  This may throw the case off because when the luminol test is used it can react with bleach and glow, but there is no certainty that there is any blood present as well.

 Ayla Reynolds was a 21-month-old toddler, who her family reported missing from their home. When investigators went to check the house, there was no visible sight of any type of break-in. They ruled out kidnapping. The chemical police decided to use liquid luminol in order to see if there was any sign of blood. When they went downstairs into the basement of the apartment they found traces of blood which tested positive for Ayla’s blood. This helped police officers determine that some of the family members were hiding something from them. No further information has been disclosed.

 Meredith Kercher was found in an Italian villa on September 2007 with her throat was slashed.  There were three individuals present when the murder took place.  Amanda Knox: American student living in the villa  Rafaelle Sollecito: Meredith’s boyfriend  Rudy Guede: A drifter  When police arrived at the scene they noticed there was lack of blood for a victim whose throat was cut.  Detectives decided to use luminol to see if there was any traces of blood and were able to find 14 luminol “hits.”  A knife was also found with Amanda’s fingerprints.

 With this evidence all three suspects were convicted of murder.  There was a retrial in order to prove Amanda’s innocence.  Blogs and other websites have been set up to show that the luminol tests were false.  It is stated that the crime scene had no traces of bleach that could have been used to wipe the blood away.  They believe that the luminol tests were wrong and led to the wrongful conviction of Amanda Knox.

 On April 3, 2013 a man by the name of Juan Lopez is found dead in his apartment.  When the room he is in is inspected they find the room in complete chaos, a clear sign of a struggle.  When examining the victim’s body, ten knife wounds were found on his torso area. A brutal scene in which one expects to see much blood, but no such blood was visible.  The victim had a roommate who states he was out at the time of the murder, but there is no one to support his alibi.  When inspecting the hallway of the home, there was a strange pattern on the floor as if someone tried cleaning with some sort of substance.

 This patter led from the room of the victims to the roommate’s room.  Detectives decided to use the luminol test because they believed someone was trying to conceal something.  The floor turned blue  Detectives also checked the roommate’s room  Traces of the blue glow led to a vent in the room.  A knife was found in the vent  The blood linked to Juan Lopez  The roommate was arrested immediately  He was found guilty and sentenced to life in prison.

 1) Name at least two things relating to a blood stain that support a particular sequence of events.  2) What happened with the Kercher case?  3) What happens if there is bleach residue at a crime scene?  4) When are investigators most likely to use Luminol?  5) What makes BlueStar Forensic so efficient?  6) What is hemoglobin and what is it used for?

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