Journal of Forensic
Identification Volume:58 Issue:1 Dated:January/February
2008 Pages:54 to 82
This study confirms that latent marks are capable of
withstanding exposure temperatures about 100 C for several hours and
identifiable marks have been recovered from a range of substrates placed in
realistic fire scenes. Sequential treatment processes can be proposed for both
soot removal and fingerprint development on articles affected by fire. Arson is
one of the most expensive crimes in terms of material cost. When examining the
scene for fingerprints, there is a misconception that fingerprints are destroyed
by the intense heat and black soot deposits arising during a fire and the effect
of extinguishing media. Until recently, there has been little published
information on the recovery of fingerprints from arson scenes. Building on
previous research discussed, this first in a two-part study examined the range
of temperatures and exposure times that latent marks could survive exposure to
heat and the effectiveness of existing development processes in developing
heat-affected marks, how these conditions were modified by the addition of soot,
and the best practice for soot removal.
https://www.ncjrs.gov/App/publications/Abstract.aspx?id=243223
Friday, June 14, 2013
Famous Arsonists and Why
- John Orr
John Orr was a former fire captain and arson investigator for the Glendale Fire Department in Southern California, and to much surprise, a serial arsonist. During the ’80s and early ’90s, there were a series of fires around the Los Angeles area that were going unsolved. Investigators noticed that the fires were started in areas next to major highways and, ironically, while arson investigation conventions were going on nearby. During the investigation, police discovered an important piece of information —a fingerprint on a time-delay incendiary device from the 1987 fire in Fresno, California. The fingerprint was linked to arson investigator John Orr. In addition to the fingerprint evidence and seized accelerating devices belonging to Orr, there was an earlier incident that sparked suspicion. Orr was one of the arson investigators assigned to a 1984 South Pasadena fire that destroyed a hardware store, killing four people. All of the arson investigators agreed that the cause was an electrical fire, but Orr insisted that it was arson. Orr was convicted and charged with three accounts of arson and is currently serving life in prison.
http://www.firesciencecolleges.com/blog/2010/10-famous-arsonists-and-why/
more info:
http://en.wikipedia.org/wiki/John_Leonard_Orr
A novel method for development of latent fingerprints recovered from arson simulation
Abstract
A diversified range of physical and chemical methods is available for the development of latent fingerprints. But fingerprints exposed to extreme conditions like fire or arson are generally perceived to have been damaged. Electromagnetic radiations, soot deposition and high temperatures are the forces generated in fire which may affect the fingerprints at the scene. Thus the potential value of highly crucial evidence like fingerprints remains unutilized. The study was conducted to determine if fingerprints could be developed after being subjected to arson/fire scene simulation. Fingerprints on non porous surfaces were subjected to high temperature, soot deposition and subsequently treated with water. A novel fluorescent and a pre existing small particle reagent was investigated for the same. Zinc carbonate based fluorescent small particle reagent was capable of developing latent fingerprints exposed to a maximum temperature of 800
°C.Fingerprints Help Solve Arson Case
UPDATED 3:08 AM CST Jan 09, 2012
Fingerprints have helped Lancaster County deputies solve a 3-year-old arson case.
Investigators believe 28-year-old Tyler Bartunek threw a firebomb into a Waverly concession trailer in May 2009.
A beer bottle used to make the Molotov cocktails was found with fingerprints on it, but deputies couldn't find a match. That is, until Bartunek was arrested on unrelated charges recently.
Investigators are now looking into whether he's responsible for any other fires in the town
Read more: http://www.ketv.com/Fingerprints-Help-Solve-Arson-Case/-/9675214/10128354/-/1088coqz/-/index.html#ixzz2WCpYbL2y
Thursday, June 13, 2013
Flame Method
The flame method can be used to process for latent prints; but it is also demonstative of why and how latent prints may be developed on some fire scene evidence.
The torch provides carbon soot, which settles on a surface. The soot sticks to the oily fingerprints. We remove the dry soot. Hopefully a fingerprint made visible by soot sticking to it remains.
This is what we may expect to find in some fire scenes: Soot provided by smoke coating a surface, soot sticking to fingerprints; removing the loose dry soot with a fingerprint brush may show us visible latent fingerprints.
Let's look at how to do this excersise:
Take a non-porous item, seed it with a fingerprint (rub your thumb on the side of your nose or forehead, and place an oily thumbprint on the item)
Make a torch with masking tape. Pull off two arm-lengths of tape. Fold the peices back on themselves, twice. Twist the tape ribon. light the end of this tape torch. Hold the item in the stream of soot / smoke eminating from the torch. Don't be too concerned about the flame, unless you are worried about your item catching on fire.
Continue until the surface with the fingerprint is coated. Now brush the soot with a fingerprint brush. the loose dry soot should be removed easily.
We should have a nice fingerprint left behind
The carbon in the soot is much finer than carbon in fingerprint powder, and develop a print with much finer detail than standard black powder.
Wednesday, June 12, 2013
http://www.flickr.com/photos/carlylehold/4029684368/
"Wall paper Cleaner to Do Be Dough
The Magic Wallpaper Cleaner
St Louis, MO
The company was founded in St. Louis by H.R.
Henderson and in 1900 the business moved into a factory
that previously housed the Mullanphy Emigrant Home.
During the early part of the century the Absorene
business grew by adding new cleaning products and
expanding sales across the country. By the mid 1940s
Absorene was the largest manufacturer of wallpaper
cleaner in the U.S.
In 1954 the company was purchased by Harry
Shear and he extended the product line to include
children's modeling dough made and packaged for many
national accounts under private label."
http://www.flickr.com/photos/carlylehold/
Play Doh a soot remover
...devised at the request of Krogers Grocery, which wanted a product that could clean coal residue from wallpaper.[5] Following World War II, with the transition from coal-based home heating to natural gas and the resulting decrease in internal soot, and the introduction of washable vinyl-based wallpaper, the market for wallpaper cleaning putty decreased substantially. McVicker's nephew, Joseph McVicker, joined Kutol with the remit to save the company from bankruptcy; he subsequently discovered that the wallpaper cleaner was being used by nursery school children to make Christmas ornaments.[1] http://en.wikipedia.org/wiki/Play-Doh
Which explains why my tub of Absorene paper cleaner, smells like Play-Doh. I bet Absorene traces it's liniage back to the origins of the pre-cursor to Play-Doh
http://www.absorene.com/absorenecleaners.html
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