Under what circumstance might an officer call a Drug Recognition Expert?

A Drug Recognition Expert (DRE) is a specialized officer trained to recognize impairment in individuals due to the influence of drugs, as opposed to just alcohol. The situation in which it becomes critical to involve a DRE typically arises when the Blood Alcohol Concentration (BAC) is inconsistent with the level of impairment observed in a suspect. For instance, if a person displays significant signs of intoxication, but their BAC is low or even within legal limits, it raises questions about whether other substances—like drugs—are affecting their behavior. In this scenario, a DRE can conduct a comprehensive evaluation to determine if drugs are involved, providing valuable insights that go beyond simple BAC readings.

The other scenarios don't necessitate a DRE's involvement. Verifying a suspect's identity and reviewing the arrest procedure do not pertain directly to impairment assessments. Additionally, calling a DRE when there is no BAC result doesn't consider the specific relevance of impairment as highlighted in the correct choice. The focus on discrepancies between BAC and observed impairment makes option C particularly relevant to the role of a Drug Recognition Expert.