Inferences, Arguments, and Second Generation Forensic Evidence

Advances in scientific and technological evidence have resulted in a new, second generation of forensic proof characterized by its high degree of probativeness and mechanical sophistication. Methods such as DNA typing are already in widespread use in the criminal justice system, and law enforcement may soon have available other biometric techniques, global locators, or even reliable lie detection systems. The promise and allure of such forms of forensic evidence lie in its high degree of accuracy. But the perception that such evidence is 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\u27s conclusions, thus implying that those conclusions did not support the defense. Lastly, the government has argued in some cases that the defendant\u27s 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 question of the proper latitude to accord both the defense and prosecution in the range of available challenges and inferences made with regard to 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