jimtrue.com : school : CJT1111 : 2003-06-04: Trace Evidence & Miscellaneous Material (Ch 7)
Posted by Jim True on June 4, 2003 6:53 AM. Last Updated October 22, 2006 9:23 PM
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Microscopic material that is often invisible to the naked eye.
Fracture Match
Difference between microscopic and macroscopic: micro is a small part, macro is the whole part.
What we use to find trace materials - Alternate Light Sources
Plants, dirt, roots are trace materials, even though you can see it.
Video Notes
Maricopa County Sheriff's dept. Deniece Johnson case. Linked to suspect from pager ownership. Vehicle also traced to the suspect. Needed to prove suspect was the killer.
Had to be linked to the scene of the murder in order to convict. Collected seed pods from the trucks. If DNA testing of the seed pods in the truck bed could be linked to the tree of origin, they would have their proof. DNA testing on seed pods had never been done. RAPIDS - Rapidly Amplified Polymorphic DNA
Compared as a control to 11 other trees at the criime scene to differentiate to the tree that had the scrapings like the truck had scraped it.
RAPDs is later processed with PCR, gel eletrophoresis to make it visible. Established Botanical DNA profiling as a powerful forensic tool.
New England coastline - grains of sand. Buried at the beach in a red satin cocktail dress. Circular pattern pattern pressed into the sand and a watch with face broken at midnight. Sand from surface and the bottom of the grave.
Kendra Hutter was the dead woman. Husband and Kendra had an open marriage. Tsone was the person he was dating that evening. Roadside embankment where he ditched the shovel. To make the charges stick needed to construct more coherent account of what happening. Scattering of sand collected in car.
Without confession, had to treat the case as if he never had a confession. Forensic Geologist, Bruce hall, shovel, blanket, debris from the crime scene and the sand from the vehicle. Concentrated on the sand samples from the bottom of the grave.
color, texture and composition. Color is used to remove samples as possible samples. Water and ultrasonic waves; size and texture of the grains. Well sorted and well rounded. Examined under polarized light microscope to determine mineral composition. Quartz & Feldspar. Proved he was with the victim and BURIED the victim (since sand was linked to sand at the bottom of the grave.).
Cher Elder, Colorado. Byron Powers (boyfriend). Lakewood Police Dept. Companion captured on surveillance camera. Luther, known sex offender, 10 year prison sentence. NecroSearch, scientists used to locate buried people and evidence. Botany, geology, entomology, forensic anthropology. Buried bodies change the ecosystem around them.
Geology, looking for disturbances in the layer. Infrared analysis, ground sweeps, aerial surveillance. 2 years after Cher's disappearance. Unburied the body 10 cm at a time. Matched with dental records.
Must attempt to prove time of death; plant roots growing into victims soft flesh. Botanist to determine age of growth; cut crosswise and stained, highlighting the characteristics of the cells. Zylen, water conducting tissue in the plant, use cell structure to determine age of cell growth.
Roots, seeds and sand.
Anything and everything is evidence.L
TRACE EVIDENCE
We're going to try to find this trace evidence that can't be seen with the 'naked eye'. Lasers and Alternate Light Sources.
ALTERNATE LIGHT SOURCES
Polylight, omnichrome, lumalight, crimescope. Attorneys will ask you how this stuff works; so must know the science behind it.
Two main functions of an ALS:
Regular light - sunlight; light bulbs are alternate light sources. Flashlights, used to find crime material, oblique lighting (fingerprints, dusty surfaces transfers and dust patterns).
Ultraviolet - locate semen at a crime scene.
Infrared - inks on checks.
Need to know: Light is a form of energy. Energy is the capacity to do work. Work is the conversion of mass to motion. any object that takes up space has mass and some weight, no matter how tiny. Take energy to move mass. Light IS energy.
Radiometer - White will reflect onto the black (black absorbs the energy) and causes movement.
Walk outside, lay down in the sun; how long before you cook. Light has energy.
Father of Light Energy for Law Enforcement - E. Roland Menzel. Worked for Texas Tech in 1976; argon-ion laser. Accidentally hit his coffee cup and saw a fingerprint on the cup. 1997 published a book about lasers and properties of fingerprints as they react to laser light.
What happened then is Law Enforcement started looking into user lasers to enhance fingerprints. Copper Vapor laser. Plasma tube filled with argon or copper gas; gas molecules were excited by electricity, produces photons and produced a very hot light. Tubes are extremely fragile (minimum of $10,000 a tube). $40-50000 for a laser. Could not be brought to the crime scene; evidence had to be transported to the lab.
ND:YAG Laser. p.112-113. Yag Laser - does not have a plasma tube; contains ruby crystals. Less expensive; if you were extremely cautious you could transport this unit to the crime scene. Problem was not a constant beam; pulsating beam, 10-20 seconds. Pinellas Co Sheriff's office has a YAG laser. Pulsating beam, upsets the stomach, hurts the eyes, etc.
LASER - Light Amplified by the Stimulated Emission of Radiation. Light bulb, electricity in a gas filled bulb. LASER is extremely high-powered light (hot light). Hot Light - monochromatic - 'One color'. One wavelength; more powerful because it is not a range of wavelengths.
All LASER's are Monochromatic. Had some misconceptions about the power you had to have to get prints to luminesce. Thought they HAD to have a hot light.
ELECTROMAGNETIC SPECTRUM - EMS
Light waves:
Gamma, XRays, UV - Visible - Infrared Microwave Radio
Violet - Indigo - Blue - Green - Yellow - Orange - Red
Short wave to Long Wave; school used to teach 'ROY G BIV' Long Wave to Short Wave
Lights measured in nanometers; 1 billionths of a meter. 25.4 millimeters in one inch. One million nano's in one millimeter. Measure light waves from peak to peak; in nanometers - nm's.
Visible light waves roughly 400-700 nanometers. Radio and microwaves get up to 350 ft. peak to peak. Ultraviolet do damage to eyes and skin; Only so many X-Rays a year. Shorter the wavelength the more power the wavelength of energy has.
Alledgedly, long wavelengths will no hurt you. Cell phone - microwaves. According to the US Govt, the longer wavelengths will not hurt you. As the visible light changes from purple to red, less energy.
Blue roughly 450 nm, Red 700 nm. Why they have both on police cars is to make sure you see squad cars.
ULTRAVIOLET - Ultra means above, above what you can see in energy or power. Infra means within or below, or below what you can see in energy or power. UV begins around 300 nm.
Make sure you have a longwave UV light; or make sure you are protecting your eyes.
Will UV destroy DNA?
All the visible light is considered white light. All the colors mixed together are white light. 186,000 mp/Second speed of light.
All wavelengths travel at the same rate of speed; short wave will have more power (X-Rays). Wavelength determines how much energy will hit.
Blue would have more power than a red, but blue would not have more energy than white light, because blue is CONTAINED in white light.
Wavelength determines level of energy and color. Shorter wavelengths have more energy; violet has more energy than red.
LASER - monochromatic - one specific wavelength. If they say a laser 450 nm, the laser is blue. Red Laser - 700 nm. Very, very powerful. Red lasers used in surgery; blue lasers TOO powerful for surgery. Had to wear protective goggles at all times. Originally thought they had to have powerful lasers. FBI had an 18 watt (not much power) Argon-Ion laser, 450 nm laser. Working on object to get a fingerprint; went away for 18 minutes, had burnt hole through evidence, wall, desk in the next room and starting to burn a hole in the next wall.
1980's Robert Baker - invented the LumaLite. Owns his own companies called Payton Scientific; IONTrace. Brumfield works for Payton Scientific and teaches the LUMALite.
LUMALite - $12000 up front without attachments.
Hazelhurst - CYVEK vacuum cyanoanalyte fingerprint fuming hood. In vacuum, developed INSIDE the plastic.
Revolutionary light that was NOT a laser - an Alternate Light Source. Arc lamp which produces an incredibly bright, white light. Band Pass Filters block out all light except the visible light spectrum you're expecting. 450 nm Band pass Filter - Blue Light. 430-480 nm spectrum. Will not destroy your evidence, because it is a range of light wavelengths, so wider range of light 40 nm range. If you're going to stare into the light, use goggles.
Basic light using with ALS is 450nm, more powerful
Chemical pigments in everything; all light is striking and it is all white. Pigment absorbs all the light except for the color of the item and that is what is reflecting that color. Red shirt absorbs everything and reflects red. White reflects all light; black absorbs all light.
Anything that you can see luminesces or glows at a different or certain wavelength. Red luminesces at 700nm. Blue luminesces at 450 nm. Chemicals can be seen; luminesce at a certain wavelength. Gasoline, makeup are all chemicals; they will luminesce under ALS.
Barrier Filter blocks wavelengths of light; white thread on another white shirt. Visible wavelength see everything. With ALS, hitting with just 450nm; Barrier filter blocks out light above a certain range or below the range. Items luminescing above the range will stand out with a certain barrier filter. Items in the lower range will stand out with a different barrier filter. We're looking for contrast to find the trace evidence.
STOKE'S SHIFT
Stoke's Shift - Shine the ALS light onto something; 450nm coming in, whatever is being shined on absorbs some of that energy. The energy being reflected back at another energy level (because some is absorbed), lesser wavelength, different color.
Have several wavelengths of ALS, have several barrier filters. Will use a range while at the crime scene.
Example: White shirt with a white thread on it from another shirt (different material, will absorb light at a different rate than the other shirt). Shining light ALS at 450 nm on both items. Shirt will absorb 50nm, reflect back light at 500nm (less energy); thread will absorb 200nm, reflect back light (luminesce) at 650nm. We'll look at the piece of evidence with a KV560 barrier filter [Blocks light below 560nm?], the background shirt will not glow because it's reflecting below 560, but the thread will luminesce because it's at reflecting light at 650
Tennis ball thrown against a wall at a certain speed; wall absorbs some energy comes back at a lower speed. Stoke's Shift.
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