In the world of crim­i­nal law truth is the gold stan­dard.  Who doesn’t want a truth­ful ver­dict?  Admit­tedly, absolute truth is often illu­sive.  But how can jurors and judges who were not at a scene, were not eye­wit­nesses them­selves to the event and do not know the cred­i­bil­ity or the accu­racy of the wit­nesses called before them trust that they will make the right deci­sions on the lib­erty of another?

The answer is phys­i­cal evidence.

in foren­sic sci­ence phys­i­cal evi­dence is very important

For exam­ple, two peo­ple see a drive-by shoot­ing.  It is an unex­pected event so nei­ther per­son was par­tic­u­larly pay­ing atten­tion or antic­i­pat­ing it.  These two peo­ple are going to have dif­fer­ent rec­ol­lec­tions and per­cep­tions as to the once in time event that was this drive-by shoot­ing.  Both folks can be totally hon­est in their belief as to what type of gun was used, the color of the gun or even who had it, yet be wrong in terms of the absolute truth.  In short, mem­ory is fun­gi­ble.  So in these instances, what can we do?  We look at the phys­i­cal evidence.

We can look for dif­fer­ent cal­ibers of shell cas­ings left at the scene to see at least how many guns were involved pro­vided we can link these cas­ings to only this once in time event.  We can attempt to do touch DNA on the spent cartridges.

In short, we can use phys­i­cal evi­dence to nar­row down the uni­verse of pos­si­bil­i­ties inde­pen­dent of eye­wit­nesses.  Then we can com­pare what the eye­wit­nesses say to see if the eye­wit­ness accounts con­flict with the known unques­tion­able phys­i­cal real­ity as given to us by the phys­i­cal evi­dence so that we may gauge the verac­ity and accu­racy of the eye­wit­nesses’ per­cep­tions of this sin­gu­lar event.

In crim­i­nal law, phys­i­cal evi­dence is king.  Phys­i­cal evi­dence does not have bias.  Phys­i­cal evi­dence exists inde­pen­dent of the hopes and wishes of any­one.  This is why it is so very impor­tant for phys­i­cal evi­dence to be dis­cov­ered, not con­t­a­m­i­nated and prop­erly analyzed.