1. Find the 6 differences between the two pictures.
Warm-Up
Find the 6 differences between the two pictures.
Source:

2. Answers: Woman’s hair, boot, glove, belly button, wall socket, dress
The answers are …
Answers: Woman’s hair, boot, glove, belly button, wall socket, dress
Source:

3. Soil Evidence

4. Forensic Geology The legal application of earth and soil science
Characterization of earthen materials that have been transferred between objects or locations and the analysis of possible origin or sources

5. Forensic Geologist Tools
Binocular microscopes
Petrographic microscopes
X-ray diffraction
Scanning electron microscopes
Microchemical analysis

6. Forensic Geology History
1887–1893—Sir Arthur Conan Doyle wrote about scientific ideas and techniques for solving crimes in his writings of Sherlock Holmes. This included information about soil and its composition which had never actually been used.
1893—An Austrian criminal investigator, Hans Gross, wrote that there should be a study of “dust, dirt on shoes and spots on cloth.” He observed, “Dirt on shoes can often tell us more about where the wearer of those shoes had last been than toilsome inquiries.”

7. Forensic Geology History
1904—Georg Popp, a German forensic scientist, presented the first example of earth materials used as evidence in a criminal case, the strangulation of Eva Disch.
1910—Edmond Locard, a forensic geologist, was most interested in the fact that dust was transferred from the crime scene to the criminal. This helped to establish his principle of transfer.

8. Soil
Definition—naturally deposited materials that cover the earth’s surface and are capable of supporting plant growth
The Earth
75%—oceans, seas and lakes
15%—deserts, polar ice caps and mountains
10%—suitable for agriculture

9. C. What Is Soil? Mixture of organic and inorganic material
May range from 100% inorganic to nearly 100% organic
Inorganic part is minerals
Organic part is decayed plant and animal material and is sometimes called humus

10. Soil D. Profile E. Composition Topsoil Subsoil Parent material
Soil horizon
E. Composition
Sand - inorganic
Silt – medium size
Clay – small, sticky
Organic matter
Loam - mixture
Peat – more than 20% humus
Chalk – basic, soft, soil with minerals

11. Soil – needed for growing
Nutrients—macro
Nitrogen
Phosphorus
Potassium
Calcium
Magnesium
Sulfur
Nutrients—micro
Manganese
Iron
Boron
Copper
Zinc
Molybdenum
Chlorine

12. Probative Value of Soil
Types of earth material are virtually unlimited. They have a wide distribution and change over short distances.
As a result, the statistical probability of a given sample having properties the same as another is very small
Evidential value of soil can be excellent

13. Increasing Probative Value
Rare or unusual minerals
Rocks
Fossils
Manufactured particles

14. Minerals More than 2000 have been identified
Twenty or so are commonly found in soils; most soil samples contain only 3 to 5
Characteristics for identification—size, density, color, luster, fracture, streak, or magnetism

15. Rocks Aggregates of minerals Types Formation Natural—like granite
Man-made—like concrete
Formation
Igneous
Sedimentary
Metamorphic

16. Sand Characteristics
Composition is based on the material of the source; also gives the sand its color
Texture is determined by the way the source was transported
Shape
Grain size
Sorting

17. Sand Types
Continental sands—formed from weathered continental rock, usually granite and quartz
Ocean floor sands—formed from volcanic material, usually basalt
Skeletal sands – formed by organic materials. (shells, algae, et), indicate warm water life
Precipitate sands —formed when calcium ions from underground springs precipitate with carbonate ions in the salt water of a salt lake

18. Source 1 – Significance of Soil
Soil is class evidence - cannot be individualized to a particular location
There is no classification system for soils
Soils can be easily transported
Soils within a few meters horizontally or vertically differ

19. Source 2 - Soil Evidence
Class characteristics—the type of soil may have similar characteristics at the primary and/or secondary crime scene, on the suspect or on the victim
Individual characteristics—only if the soil has an unusual or specialized ingredient such as pollen, seeds, vegetation, or fragments.

20. Soil Comparisons
May establish a relationship or link to the crime, the victim, or the suspect(s)
Physical properties—density, magnetism, particle size, mineralogy
Chemical properties—pH, trace elements

21. Forensic Analysis of Soils
Bulk analysis
Density gradient
Particle size distribution
(sieving)
Inorganic components
Color (dissolve in water)
Petrography - mineral analysis; Requires a good deal of skill and practice

22. Forensic Analysis of Soils
Organic components
Liquid chromatography
Oxygen availability
Bacterial DNA? - Future possibility

23. Collecting Soil at a Scene
Collect samples ASAP
Collect baseline samples and samples that look different or out of place
Collect from different locations (4 tbs. min)
Collect from compass points around crime scene and again 20 to 25 feet away
Include location of samples on sketch
Package separate from other evidence
Document the collection

24. Death of a DEA Agent: Enrico Camarena
Story of how FBI geologist, Ron Rawalt was able to determine, with certainty, where Camarena body was buried, thus showing that Mexican govt. lied about how he was killed.
He noticed a TV report of the killings. The body was shown with soil clinging to it. The soil was obviously of a different color than the soil from the alleged burial site.

25. Death of a DEA Agent: Enrico Camarena (cont)
He told the govt. that he could prove, with soil analysis alone, that Mexican govt. was lying about the murder.
He went to Mexico and collected a spoonful of soil from Camarena body. He compared that to the soil from the alleged burial site and found them to be entirely different.

26. Death of a DEA Agent: Enrico Camarena (cont)
Soil from body
Spoke of mountains
98% rhyolite ash (clean, high in silica, angular, vesicular) – could be described as “airfall pumice”
Bixbyite – blacker than coal
Pink glass of exceptional depth and richness of color, he had never seen anything like it, except in candy
2 kinds of cristobalite: opalized and clear, elongate and faceted, clear polygonal columns (octehedrons). Resembled branch coral. Very rare to find both types together.

27. Death of a DEA Agent: Enrico Camarena (cont)
Pinpointing location
Research with Geological Survey and Smithsonian minerologists located specific location – A Jalisco state park called Bosques de la Primvera. Cristabolite was the result of a third-event calderea formation.
Location is on upslope of mountain in park or park itself
Rawalt flew to Mexico as “DEA agent” (FBI agents were not allowed in to investigate

28. Death of a DEA Agent: Enrico Camarena (cont)
While Rawalt was in Mexico searching for the area of burial, FBI was approached about a French consultant, Loic Le Ribault. He was the head petrologist for the French national oil company and was said to be able to do things geologically speaking, that other people couldn’t do. Show him a few grains of sand and he could tell you where they came from

29. Death of a DEA Agent: Enrico Camarena (cont)
Le Ribault
FBI tested him by giving him 3 samples:
Ash from Mt. St. Helens
Alluvium from river delta in S. Carolina related to recent murder
Dirt from girders taken from bomb site in Beirut, Lebanon
Ribault’s results:
Got location of ash from Mt. St. Helens within a few miles of source
River basin in American Southest
Bekaa valley in Lebanon – soil had been subjected to explosion

30. Death of a DEA Agent: Enrico Camarena (cont)
Le Ribault’s contribution to Camarena case
Was showed samples from park and body. He said “you are there, but not there”. Right elevation, but these are samples (from park) from an area washing north. The site is an area washing south.
Sand deposited by water 4-5 ft. deep in a draw. Slope of draw <10 degrees. Shade predominates.
Rawalt found exact location from this data.