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Soils and Soil Analysis

Soils and Soil Analysis

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Soils and Soil Analysis

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  1. Soils and Soil Analysis

  2. What Is Soil? • Mixture of organic and inorganic material • May range from 100% inorganic (sand) to nearly 100% organic (peat) • Inorganic part is minerals • Organic part is decayed plant and animal material and is sometimes called humas

  3. Forensic 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

  4. 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

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

  6. Some Interesting? Cases Where Geological Evidence Has Been Important • Florida v. William Kennedy Smith • South Dakota v. Donald Eugene Moeller • Colorado v. Walter Osborne • The Death of a DEA agent – Enrico Camarena

  7. Florida v. William Kennedy Smith • WKS accused of rape of Patricia Bowman • Alleged attack on grass lawn behind Kennedy estate in W. Palm Beach, Fl • WKS alleged consensual sex on the beach near estate • Jay Siegel used PLM to compare samples from clothing of victim to lawn and beach areas • Samples consistent with beach, not lawn • WKS acquitted of rape

  8. South Dakota v. Donald Eugene Moeller • Capital murder case of 9-year old Becky O’Connell on May 8, 1990. • Testimony by soil expert refutes defendant alibi • Victim snatched off street, raped, killed, body dumped in woods. • Suspicion fell on Defendant because of prior sex crime involvement. • Found guilty and sentenced to death. Appeal resulted in reversal owing to admission of evidence of prior bad acts.

  9. South Dakota v. Donald Eugene Moeller (cont.) • SD Supreme Court reversed and reinstated conviction • State geologist analyzed soil found in wheel wells of defendant pickup truck. Issue was whether soil came from crime scene South of Sioux Falls or from a road North of Sioux Falls where defendant claimed he was at time of crime • Geologist testified that soil could have come from crime scene. • Opinion based on: • Colors and general characteristics • Soil was much lighter or could not have come from other roads in area • “Sharp, clean” hornblende crystals much more likely to have come from crime scene area

  10. South Dakota v. Donald Eugene Moeller (cont) • Part of appeal called for striking geologist’s testimony as being too speculative as to conclusions • At 2nd trial, geologist came into more evidence from scene and wheel well: dark green to black gahnite found at scene and in evidence from truck. This mineral extremely rare.

  11. South Dakota v. Donald Eugene Moeller (cont) • Defense argued that geologist erred in identifying gahnite only by visual inspection. Claimed that PLM should have been used (to confirm that gahnite is isotropic) and that x-ray diffraction should have been used to confirm. Appeals court rejected appeal • There was no discussion at trial whether the finding of both hornblende and gahnite near Sioux Falls was a rarity or could be due to processing after mining elsewhere. Bedrock of Sioux Falls contains neither hornblende nor gahnite.

  12. Colorado v. Walter Osborne • Osborne botches kidnapping of Adolph Coors from his ranch near Morrison and kills Coors • Ranch is near “Dakota Hogback” which is made of Dakota sandstone underlain by gray, green and maroon clay stones, shales, more sandstone and limestone. Dirt road near ranch was essentially eroded, pulverized components of hogback.

  13. Colorado v. Walter Osborne (cont) • During kidnapping, a fight broke out and Osborne shot Coors. Fled in Osborne’s yellow Mercury with body. Fled south onto an unpaved road in next county. Then went west and climbed. Road made of muddled dust; pink-feldspar. Dust was granite, but compared to bedrock was deficient in iron and magnesium. • As he climbed further, came into Pike’s Peak granite – very distinctive.

  14. Colorado v. Walter Osborne (cont) • At 7200 ft, Osborne dumped body in dump used by an Ashram. Body would not be found for 7 months. • Osborne went east and went on an unpaved road of black slags and drifted sands on a New Jersey barrier island. He hid car and torched it with gasoline.

  15. Colorado v. Walter Osborne (cont) • FBI investigation turned up Osborne in New Jersey • Although Osborne (discovered to be Joseph Corbett, Jr) covered his tracks well but was writing his itinerary on the bottom of his car. • 4 depositional strata found: • 4th contained material from around New Jersey dump where he burned car • 3rd contained pink feldspars of Pike’s Peak granite – near where body was found • 2nd had materials from Morrison hogback formation – around Coor’s rangch • 1st had pink feldspars of other Front Range granites – generally related to Rocky Mountain Front Range

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  21. 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

  22. 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.