Inferences, Arguments, and Second Generation Forensic Evidence

Abstract

Advances in scientific and technological evidence have resulted in a new, second generation of forensic proof characterized by its high degree of probativeness, mechanical sophistication, and database-based investigative capacity. Methods such as DNA typing are already in widespread use in the criminal justice system, and law enforcement may soon have commonly available other novel techniques such as advanced biometrics, electronic locators, or even reliable lie detection systems. The promise and allure of such forms of forensic evidence rest in its high degree of accuracy. But the perception that such evidence is effectively infallible has resulted in an increasing number of instances in which the government has sought to bolster its case by making arguments based on actions taken, or not taken, by the defense. In some cases, the government appropriates a nontestifying defense expert as its own. In others, the government presents evidence that the defense sought expert assistance but then did not present the expert's conclusions, thus implying that those conclusions did not support the defense. Lastly, the government has even argued in some cases that the defendant's failure to seek expert assistance supports an inference of guilt, because an innocent person would have made efforts to disprove such powerful and inculpating evidence.

This Article explores the proper range of latitude to accord both the defense and prosecution in making challenges and inferences regarding scientifically or technologically sophisticated evidence. More specifically, this Article concludes that resolution of such questions requires informed and close attention to the particular characteristics of second generation scientific evidence.

Keywords: DNA, Forensic, Science, Evidence, Missing Witness, Criminal Law, burden shifting

JEL Classification: K14