Forensic sciences 2 I.Lesson on forensic sciences 1. Introduction & definition 2. History 3. Technics : DNA profiling Fingerprints BPA Forensic chemistry Ballistic PLAN 3 Introduction When forensic sciences were used at the first time ? When forensic sciences were used at the first time ? When fingerprints were used at the first time in order To solve a crime ? When fingerprints were used at the first time in order To solve a crime ? 8 History 9 Technics a. DNA Profiling How many DNA sequences are the same in everybody ? - 0,01 % - 30% - 60% - 99,9% 10 Technics a. DNA Profiling How many DNA sequences are the same in everybody ? - 0,01 % - 30% - 60% - 99,9% 11 Technics a. DNA Profiling * 99.9% of human DNA sequences are the same in every person. - 0,01% is different to distinguish one individual from another. - DNA profiling uses Variable Number Tandem Repeats VTNRs STRs * DNA Database USA : ~ 9 million records (2011) UK : ~ 9 million records (2011) France : ~ (2009) 12 Technics b. Fingerprints - 3 big types : - All fingerprints have specific points witch are differents. Probabilty that 2 persons have the same fingerprints : 1 for 64 billions - Twins dont have the same fingerprints ! 13 Technics b. Fingerprints Examples : Points of differenciation 14 Technics b. Fingerprints Examples : Points of differenciation 15 Technics b. Fingerprints Examples : Points of differenciation 16 Technics c. Fingerprints Examples : Points of differenciation 17 d. Technics Where does Dexter work ? (The famous Serial Killer) - Biometric analysis - Bloodstain pattern analysis - Secret Agent - English Teacher 18 d. Technics Where does Dexter work ? (The famous Serial Killer) - Biometric analysis - Bloodstain pattern analysis - Secret Agent - English Teacher 19 - Applies scientific knowledge : Scientific disciplines of biology, chemistry, mathematics and physics - Provide strong and solid evidences. - Use in solving crimes and apprehending offenders d. Bloodstain pattern analysis (BPA) Technics 20 Technics e. Forensic chemistry * Methods : - Spectroscopy Analyse of IR spectrum - Chromatograph (Gas chromatography) - Luminol Molecule of luminol A crime scene revealed by luminol 21 Technics e. Forensic chemistry What does luminol reveal ? - the oxygen into the blood - the iron into the blood - the plasma into the blood - bacteria into the blood 22 Technics e. Forensic chemistry What does luminol reveal ? - the oxygen into the blood - the iron into the blood - the plasma into the blood - bacteria into the blood 23 Technics f. Ballistic Area of Forensic Science that deals with firearms. * The condition of the victim can tell a lot about the nature of the weapon. * Most guns have their own unique identifying features * Information can be determined from - Bullet - Nature of the wound - Residues * Study of trajectories / degree of penetration in the target estimate the position of the shooter (and the shot distance). 24 Technics f. Ballistic What is the name of this ? - Hammer - Trigger - Grip 25 Technics f. Ballistic What is the name of this ? - Hammer - Trigger - Grip