Specimens were spiked with deuterated analogs of the analytes. Urine specimens were enzymatically hydrolyzed and blood specimens were untreated. Extractions were carried out and drugs were separated on a column using a methanol-water-ammonium hydroxide mobile phase. After the determination of base peaks using full scan MS, the MS method was optimized to operate in selected ion monitoring mode for the base peak of each analyte. Positive findings were confirmed by LC/MS/MS using the same mobile phase and column. The authors conclude that the analytical procedure allows for the detection of low levels of flunitrazepam and metabolites in biofluids and that it is useful in ascertaining the role of flunitrazepam in cases of drug-facilitated sexual assault. 13 references, 1 table, and 5 figures