Warm-UpDecember 4, 2014

• What are examples of low explosives?

• What are examples of high explosives?

Objective

• SWBAT explain how to collect and analyze evidence in suspected arson cases and explosions.

Agenda

1. Mini-Mystery2. Follow the Case3. Detection4. Collection & Analysis5. Cases6. OKC Bombing Documentary7. Nuclear Bombs8. Exit Slip

One evening as Max was out walking, Mrs. Zenitt called his name. He hurried across the street. She was standing in her front yard, but she guided him around to the back. "I was watching TV in the living room," she told him, "and I heard a crash. Just look!" She pointed to her back porch window. "Someone threw a rock through it. It's broken into a dozen pieces!“

"Do you know who did it?" he asked.

"No,” she replied, “He ran off, but I think maybe it was David Loring. We had a spat the other day because I told his parents he had to stop using my yard as a short cut. But I wouldn't accuse him of breaking a window without more proof.“

"I'll talk to him," Max said.

Source: http://kids.mysterynet.com/quicksolve/

He found David panting as he bounced a basketball under the light on his garage. "Did you just run from Mrs. Zenitt's?" Max asked. "Did you break her window?"

David shook his head. "No. I'm all out of breath because I've been out here shooting baskets. I don't know anything about a broken porch window."

"You're not telling the truth," Max said.

How did Max figure it out?

Max knew David was not telling the truth because he said "porch window." Max had not mentioned which of Mrs. Zenitt's windows had been broken. "This case was a real pane, but the

solution was as clear as glass," Max told Nina later.

14-7©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Follow that Case

• http://www.interfire.org/features/followThatCase/episode001.asp

14-8©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Detection• Get in groups of 3

• Divide up the three articles

• Read the article and you will give your group a summary

• http://www.sciencedaily.com/releases/2009/03/090313150117.htm

• http://www.technologyreview.com/news/410212/portable-plastic-explosives-detector/

• http://www.pbs.org/wgbh/nova/nature/dogs-sense-of-smell.html

14-9©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Collection and Analysis• The entire bomb site must be systematically

searched with great care given to recovering any trace of a detonating mechanism or any other item foreign to the explosion site.

• Objects located at or near the origin of the explosion must be collected for laboratory examination.

14-10©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Collection and Analysis• Often a crater is located at the origin and loose

soil and other debris must be preserved from its interior for laboratory analysis.

• One approach for screening objects for the presence of explosive residues in the field or laboratory is the ion mobility spectrometer (IMS).

14-11©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Collection and Analysis• Preliminary identification of an explosive

residue using the IMS can be made by noting the time it takes the explosive to move through a tube. A confirmatory test must follow.

• All materials collected for the examination by the laboratory must be placed in sealed air-tight containers and labeled with all pertinent information.

14-12©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Back at the Lab• Typically, in the laboratory, debris collected at

explosion scenes will be examined microscopically for unconsumed explosive particles.

• Recovered debris may also be thoroughly rinsed with organic solvents and analyzed by testing procedures that include color spot tests, thin-layer chromatography, infrared spectrometry and gas chromatography–mass spectrometry.

14-13©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Back at the Lab• Confirmatory

identification tests may be performed on unexploded materials by either infrared spectrophotometry or X-ray diffraction.

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14-14©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

X-ray Diffraction• X-ray diffraction is applied to the study

of solid, crystalline materials.

• As the X-rays penetrate the crystal, a portion of the beam is reflected by each of the atomic planes.

• As the reflected beams leave the crystal’s planes, they combine with one another to form a series of light and dark bands known as a diffraction pattern.

14-15©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

X-ray Diffraction• Every compound is known to produce its own

unique diffraction pattern, thus giving analysts a means for “fingerprinting” crystalline compounds.

14-16©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

X-Ray Diffraction Results•

14-17©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Modern Bombs

14-18©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Famous Bomb Sites

14-19©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Famous Bombings • Oklahoma City Bombing 1995 , 168 dead

• Twin World Trade Center 1993 & 2001 , 3000 dead after 9-11.

• US Embassy barracks 1983

• USS Cole while in port October 2000

• Pan Am Flight Lockerbie, Scotland: N.Y.-bound Pan-Am Boeing 747 exploded in flight from a terrorist bomb and crashed into Scottish village, killing all 259 aboard and 11 on the ground

Listing of bombings web site

The Role of Forensic Science in the Investigation of Major Acts of Terrorism

Introduction

• A major terrorist act can generate huge amounts of evidence that can help in the investigation

• Different acts call for different strategies• We will examine three major terrorist acts in

the US with emphasis on the forensic science aspects:• World Trade Center Bombing• Murrah building in Oklahoma City bombing• World Trade Center destruction

The World Trade Center Bombing

The Scenario

• Urea nitrate bomb put into truck and driven into underground WTC garage and parked at 4th level down

• Subsequent explosion did extensive damage to several levels of the garage and less damage to other levels

• Although goal was to topple WTC, little structural damage was done

• Some loss of life

Goals of Investigation

•Identify victims•Identify explosive•Recover bomb and timing

device•Determine method of

delivery

Evidence Sought

• Investigators had to remove large quantities of concrete, steel and cars to get to bomb seat

• Bomb seat contained most of the important evidence

• Bomb parts; timer, casing, etc.• Explosive residue• Parts of truck that contained

explosive

Areas of Forensic Science

• Explosives• Engineering• Questioned documents• Fingerprints• Pathology• DNA

The Murrah Building, Oklahoma City

The Scenario

• ANFO explosive and timer packed into a rented truck, which was then parked outside Murrah building

• Explosive confined to closed space such as truck is much more powerful

• Resulting explosion caused severe damage to building and loss of more than 100 lives

Goals of Investigation

•Identify victims•Identify explosive•Find timer and bomb parts•Determine method of

delivery

Evidence Sought

• Easier to find than in WTC because bomb seat outside building

• Explosive residues• Bomb parts• Bodies and body parts• Personal effects; helps in

identification of human remains

Areas of Forensic Science

• Anthropology• DNA and serology• Pathology• Entomology• Explosives• Trace evidence• Engineering• Questioned documents• Fingerprints

WTC Destruction

The Scenario

• Large airplanes, loaded with fuel, crash into WTC buildings

• Raging fires ignite everything in building above crash sites.

• Metal supports melt from heat• Building collapses due to inability to

support its own weight after structural damage

• Thousands of people killed

Goals of Investigation

• Cause known, no need to determine how destruction occurred

• Recover and identify bodies, parts of bodies and charred remains

• Recover personal effects that might help identify victims or perpetrators

• Evidence that might determine how hijackings occurred.

Evidence Sought

• Bodies and body parts• Charred remains• Personal effects• Trace evidence such as charred

papers• Weapons such as knives• Constraining devices such as wire

Areas of Forensic Science

• Anthropology• DNA and serology• Odontology• Pathology• Entomology• Trace evidence• Questioned documents• Fingerprints• Tools and toolmarks

OKC Bombing Documentary

20. Why did Jones not call witnesses to testify?

21. What was the public admission by the FBI in 2001 and how did this affect McVey?

22. What did Jones say was McVey’s purpose?

CASE STUDY 1The Bali bombings

Overview• In 2002, the Bali bombings killed 202 people from 22

countries• “Operation Alliance” involved Australian Federal Police

(AFP), Indonesian National Police (INP), Victoria Police Forensic Services Centre (VPFSC), Britain Forensic Explosives Laboratory (FEL), etc.

• 3 explosions: a bar, a night club, a street outside American and Australian consulate buildings

• Forensic chemists used a “mobile laboratory” to recover residues from blast scenes and suspect’s residences to determine bomb compositions

THE EVIDENCE

Bomb 1-tiny fragments of tartan fabric were recovered from site surrounding the blast epicentre-connective tissue and spatter marks were visible on the ceiling above the epicentre-absence of a crater

Bomb 2-inspection number found on chassis rail of car was traced back to owner

Explosions• result from a rapid release of gas• two main types of explosives: low velocity and high

velocity1. Low velocity explosives, like ammonium nitrate, used

mainly in mining and for “pushing” applications2. High velocity explosives, like pentaerythritol tetranitrate

(PETN) and TNT, used in detonators, military etc. Usually used to initiate/boost low velocity explosives. Usually consumed and rarely leave traces

• most large bombs consist of some form or combination of nitrate, chlorates, perchlorates, diesel oil, sugar, sulphur and/or aluminum dust

• release of this amount of energy often causes fires

Chemical Structures

• PETN

• TNT

Sample Collection• Blast scenes are complex due to the spread of

microscopic fragments that can contaminate evidence

• the concentration of the inorganic ion must be significantly higher in and around the crater than in the background

• the main blast produced a fire which was fought with water, compromising much of the blast scene

• “mobile laboratory” was used to gather evidence in a timely matter

Mobile Laboratory

• Nearby motel room was cleared and equipped with a microscope and camera, an ion mobility spectrometer (IMS), a portable infra-red spectrometer (FT-IR), reagents for presumptive tests

• Produces rapid tentative results• Samples must still be sent to main lab for

exhaustive analysis

Sample Testing• Chlorate ion was detected in 6/2000 samples analyzed

which was considered significant because the highly reactive nature of chlorate ions make it difficult to persist in the environment

• Sites it was detected on include the crevices of the blast crater, and on lamp posts facing the blast

• It was argued that the chlorate ions originated from unburnt matches falling during the blast so samples were taken from elevated surfaces

• Scientists from FEL searched the pitting of aluminum street signs that had been blasted to nearby rooftops using an SEM EDX. They reported elevated levels of chloride, low levels of chlorate, and no sulphur was detected.

Presence of TNT at two of the sites was detected by IMS and confirmed by both GC–TEA and GC–

nciMS

Colourimetric Methods For Explosives Screening

Types of Bombs

• Bomb 1 – 1-5 Kg of TNT packed into 5 lengths of PVC pipe sewn into a vest, set off by a suicide bomber

• Bomb 2 – approx. 1 tonne of explosive packed into 12 filing cabinets in a van, cabinets connected via detonating chord made from PETN, explosives a mixture of potassium chlorate, sulphur and aluminum boosted with TNT, the power was equivalent to 150 Kg TNT, set off by a suicide bomber

• Bomb 3 – small amount of TNT set off by a mobile phone

14-51©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Nuclear Bombs• Normal chemical explosions are different from

nuclear bombs in that they only use the electron bonds for energy.

• Nuclear bombs use the atomic binding force from the center of the atom. There are two types of nuclear bombs: Fission and Fusion. Reference web site Fission bombs split the nucleus.

• Fusion bombs combine nuclei into larger atoms. • Nuclear bombs are thousands of times more

powerful than chemical bombs. The biggest nuclear bomb ever made was equal to 50 million tons of TNT. Web site video

14-52©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

History of Nuclear Bombs• The atomic bomb was first developed by

German and American scientists including Einstein. The first two fission bombs were used by the USA on Japan to end WWII. These are the only 2 ever used during war on an enemy.

• Over 2000 have been exploded in testing• The damage from nuclear bombs would

be much greater than chemical bombs. Video

Video

14-53©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Fission Nuclear BombsVideo

14-54©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Fusion Nuclear BombVideo

14-55©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458

FORENSIC SCIENCE: An Introduction, 2nd ed.By Richard Saferstein

Fusion Nuclear Bombs

How to survive

Video

Unit 6 TrackingVocabulary Blood TypingA)1-21 A)22-27, 31-32B)16-36 B) 37-42, 4-5Total = 21 points Total = 8 pointsBlood Spatter AnalysisA)28-30, 33-42B)1-3, 6-15C)Total = 19 points

Homework

• Read Chapter 15, pgs. 508-520 and complete review #1-16

Exit SlipDecember 4, 2014

Go to m.socrative.com and enter 417101

Question: What is the procedure for collecting evidence?