Issues in Criminal Justice and Technology-unit 10: forensics

Problems:
Lay people tend to put total faith in DNA fingerprints, but it isn't an automatic, fail-safe technique, however:

poor handling may result in contaminated sample, environmental factors may result in its degradation , labs may be run poorly, etc.
DNA evidence can be planted at the scene.
Major backlog in untested convicted offender data base samples.
Both the science of DNA profiling and testing protocols have been questioned (as a result, the National Institute of Standards and Testing (with NIJ funding) developed Standard Reference Material (SRM) 2390 containing a set of materials to be used when doing analysis. It "enables forensic scientists to ensure right answers and pinpoint when and where mistakes are made. The standard also lets labs show that its daily working standard is traceable to NIST, which is important if lab results or test protocol are challenged in court."
1996 NAS report stressed that investigators and crime scene technicians must use meticulous care in gathering evidence and in maintaining the chain of custody. The committee suggested that evidence be divided into two parts, with one set aside for testing by a second laboratory if requested by the defense. It also advised crime labs to seek accreditation for DNA analysis by the American Society of Crime Lab Directors.

Readings:

Crime Scene Investigation technology

High-Definition Surveying
creates a virtual crime scene that can be constantly revisited, seen from different perspectives:

originanally developed for civil engineering
it projects laser light in a 360 degree horizontal circumference. As the light hits objects, it reflects back in a "point cloud" of light that is registered by a digital sensor.
These millions of data points are used to create 3-D spatial coordinates to create the virtual crime scene.
among other benefits, it's easier to show a jury a 3-D representation.
eliminates the bias seen in crime scene photos or artists' representations.
Perhaps most important, it can reduce contamination of the crime scene: create the 3-D representation when you first approach the scene, so that nothing is disturbed. One British expert says he uses SDS as a "stand off" device, so he can approach the scene in stages by scanning from the outer perimeter and then move to the middle.
"The system also has training applications. Currently there are driving, pursuit and use-of-force simulators. Using HDS, police officers could be taken into a virtual world to practice their skills, or taken back to actual events and debriefed on their own or other police officers' actions."

Example of a map (in this case, part of the Big Dig) done with the technique:

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