Whether the inference allowing a trier of fact to find knowing use of a drug based solely on the presence of a metabolite in a defendant's body, even when that inference is contradicted by the prosecution's scientific evidence, is unconstitutional?

Master Sergeant (MSgt) Adam S. Kelnhofer served over nineteen years in the United States Air Force. He was a respected non -commissioned officer with no history of substance abuse . On a rando m urinalysis test, MSgt Kelnhofer tested positive for cocaine at 116 ng/ml , just 16 ng/ml over the Department of Defense’s cutoff level. This positive test result occurred less than a year before MSgt Kelnhofer was eligible to retire. The Government prosecuted MSgt Kelnhofer for cocaine use but presented no evidence that MSgt Kelnhofer knowingly ingested cocaine, an element of that offense. Instead, the Government relied on a “permissive inference.” This inference allows military triers of fact to find a service member knowingly use d an illegal drug so long as a metabolite for that drug is in the servicemember’s body. This inference may be used regardless of scientific evidence directly contradicting it . The question presented is: Whether the inference allowing a trier of fact to find knowing use of a drug based solely on the presence of a metabolite in a defendant’s body , even when that inference is contradicted by the prosecution’s scientific evidence, is unconstitutional?