Firearm and Toolmark Identification PDF

Firearm and toolmark identification Standard Test Method for the Examination and Testing of Firearms ‫وفاء احمد على‬/‫د‬ ‫جامعة العريش‬ ⚫ What is forensic ballistics? Forensic ballistics involves the examination of evidence from firearms that may have b...

Firearm and toolmark identification Standard Test Method for the Examination and Testing of Firearms ‫وفاء احمد على‬/‫د‬ ‫جامعة العريش‬ ⚫ What is forensic ballistics? Forensic ballistics involves the examination of evidence from firearms that may have been used in a crime. When a bullet is fired from a gun, the gun leaves microscopic marks on the bullet and cartridge case. These marks are like ballistic fingerprints. If investigators recover bullets from a crime scene, forensic examiners can test-fire a suspect’s gun, then compare the marks on the crime scene bullet to marks on the test-fired bullet. The examiner will then assess how similar the two sets of marks are and determine if the bullets are likely to have been fired from the same gun or different guns. Cartridge cases are compared in the same way. ‫ما هي المقذوفات في الطب الشرعي؟ يتضمن الطب الشرعي المقذوفات فحص األدلة من األسلحة‬ ⚫ ‫ تترك‬،‫عندما يتم إطالق رصاصة من مسدس‬. ‫النارية التي ربما تكون قد استخدمت في جريمة‬ ‫هذه العالمات تشبه بصمات األصابع‬. ‫البندقية عالمات مجهرية على الرصاصة وعلبة الخرطوشة‬ ‫ فيمكن لفاحصي الطب الشرعي‬،‫إذا استعاد المحققون الرصاص من مسرح الجريمة‬. )‫(ال تتكرر‬ ‫ ثم مقارنة العالمات الموجودة على رصاصة مسرح‬،‫اختبار إطالق النار من مسدس المشتبه به‬ ‫سيقوم الفاحص بعد‬. ‫الجريمة بالعالمات الموجودة على الرصاصة التي تم إطالقها أثناء االختبار‬ ‫ذلك بتقييم مدى تشابه مجموعتي العالمات وتحديد ما إذا كان من المحتمل أن يكون الرصاص قد‬ ‫تتم مقارنة حاالت الخرطوشة بنفس الطريقة‬. ‫تم إطالقه من نفس البندقية أو من أسلحة مختلفة‬  Terms and Definitions ⚫ Field Test: Testing the operating condition of a firearm without ammunition. ⚫ Function Test: The examination of a firearm concerning its mechanical condition and operation. It is usually performed to determine if all safety features are operable and/or if the firearm is capable of firing a cartridge. ‫ يتم إجراؤه عادة ً لتحديد‬.‫فحص السالح الناري من حيث حالته الميكانيكية وتشغيله‬ ‫أو ما إذا كان السالح الناري‬/‫ما إذا كانت جميع ميزات السالمة قابلة للتشغيل و‬ ‫قادرا على إطالق خرطوشة‬ ً ⚫ Test Fire: To discharge a firearm in a laboratory or controlled setting in order to obtain representative bullets and cartridge cases for comparison or analysis, or to determine functionality of the firearm. ‫اختبار إطالق النار إلطالق سالح ناري في مختبر أو بيئة خاضعة للرقابة (في بوكس مليان ماء او‬ ‫ أو‬،‫قطن) من أجل الحصول على رصاصات تمثيلية وحافظات خرطوشة للمقارنة أو التحليل‬ ‫لتحديد وظيفة السالح الناري‬  Physical Examination ⚫ Describe the firearm to include the following, if known: Make/manufacturer Firearm type (shotgun, rifle, pistol, revolver, etc) Model Caliber/gauge Serial number Action type (semi-automatic, lever action, bolt action, etc) Construction (e.g. polymer, metal type, etc.) Inspect the bore(s) of the firearm Rifling type (e.g. polygonal or conventional) Number of lands and grooves Direction of rifling twist  Examination to suspected weapon 1. Examination to criminal bullet ⚫ Caliber ⚫ Marks 1- (number, diameters and width of lands or grooves) 2- Depth of grooves 3-Direction of grooves 2. Examination to criminal empty cartridge case ⚫ Marks ⚫ Firing pin (Concentric or Eccentric)  Examination to suspected weapon 3. Firing test of suspected weapon ⚫ Using comparative microscope 4. Examination of chemical residues in barrel ⚫ Used to detect crime weapon or time of firing ‫‪.1‬فحص الرصاصة‬ 1. Striation marks due to rifling of gun barrel 2. twist direction Close Up, Forensics Ballistics Rifling Marks on Bullet Also Known As Land Impressions and Groove Impressions bullet show left twist ‫‪2.‬فحص الظرف الفارغ‬  ‫طلقة مضروبة‬ ‫‪ The firing pin‬‬ ‫‪strikes the primer‬‬ ‫)‪(primer is dented‬‬ ‫عالمة ابرة ضرب النار ‬ ‫مطبوعة على قاعدة‬ ‫‪.‬المظروف‬ ‫طلقة غير مضروبة‬ ‫)‪ (primer is not dented‬‬ ‫‪3.‬فحص المسدس‬  cartridge compatible with pistol gun Pistol Rifle Cartridge compatible with rifle  Shotgun Cartridge compatible with shotgun  Rifled weapon cartridge The cartridge of rifled weapon consists of: 1- Bullet or missile with nickel or brass jacket. 2- Cartridge case 3- Powder smokless (white). 4- Base of brass. 5- Percussion cup or primer Cartridge of Automatic weapon(rimless) bullet Cartridge case rimless  Automatic Non-automatic Rimless Rim Lead styphnate Primer Barium nitrate Glass powder Antimony sulfide K chlorate Mercury (II) (USA) fulminate  Non-Rifled weapon cartridge 1- Brass base 2- outer case( plastic, cardboard or metal) 3- Black or smokeless powder 4-Thick internal wad 5-Rounded lead shots between the wads. 6-Thin external wad Medico legal importance of regular lead shot or pellets:- 1- Know type of weapon. 2- Distance of firing. ‫ كرات الرش‬pellets Slug Non rifled Cartridge shots Plastic cup instead of wad Explosive powder Different types of powder Cordite(smokeless) Black powder Plastic cup instead of wad  4. Examination of chemical residues Gunshot residue (GSR), also known as cartridge discharge residue (CDR), gunfire residue (GFR), or firearm discharge residue (FDR), consists of all of the particles that are expelled from the muzzle of a gun following the discharge of a bullet. It is principally composed of burnt and unburnt particles from the explosive primer, the propellant (gunpowder), and vaporized lead. The act of firing a bullet incites a very violent explosive reaction that is contained within the barrel of the gun, which can cause the bullet, the barrel, or the cartridge to become chipped. Meaning gunshot residue may also included metal fragments from the cartridge casing, the bullets jacket, as well as any other dirt or residue contained within the barrel that could have become dislodged.  Questions How can you tell that this bullet has not been fired? (A) the primer is not dented 1. (B) the primer is dented (C) there are no striations (D) the headstamp is readable What tool is used to compare striations of fired bullets? (A) compound microscope 2. (B) comparison microscope (C) scanning electron microscope (D) transmission electron microscope Comparison must show _______ striations for a for a positive match (A) Identical match of 3. (B) 50% match of (C) 20% match of (D) 85% match of What are the Griess test, lead residue test, and diphenylalamine test used for? A. GSR testing 4. B. electrophotometry C. spectroscopy D. bullet trajectory tests  What 3 elements must be present for GSR to be used in court? A. lead, antimony, barium 5. B. lead, copper, barium C. antimony, barium, nickle D. barium, cadmium, antimony Gun barrel marking left on a spent bullet are called A. striations 6. B. linear markings C. bullet fingerprints In the Sodium Rhodizionate test, what color will CONFIRM the presence of lead? A. Pink 7. B. dark blue C. yellow D. green Why test for nitrites if nitrites are not present in GSR? A. Tests are never conducted for presence of nitrites 8. B. Nitrites are a byproduct of the combustion of GSR C. Nitrites are present in the metals that make up the actual firearm D. Nitrites ARE present in GSR and therefore tested Define Striations A. marks made as the cartridge is removed from the chamber 9. B. marking from a firing pin on the cartridge C. scratch marks left on the projectile by rifling lines of the inside of the barrel D. Marks or scratches made when the cartridge is placed into the chamber  Using the image, label the parts 1: bullet. 2: gunpowder. 3: primer. 4: rim. 5: case/shell 1: bullet. 2: case/shell. 3: gunpowder. 4: rim. 5: primer 10. 1: bullet. 2: rim. 3: gunpowder. 4: case/shell. 5: primer What type of gun is this? pistol 11. revolver shotgun Rifle The cartridge headstamp contains information on a bullet's ________. (you may select more than one,) Caliber Manufacturer 12. Speed Metal Owner What type of gun is this? pistol revolver 13. shotgun Rifle