Final answer:
The detective asks about the suspect's schooling in a case study interrogation to assess the suspect's level of education and intelligence.
Step-by-step explanation:
In a case study interrogation, the detective might ask the suspect about his schooling to assess the suspect's level of education and intelligence. This information can be helpful in understanding the suspect's ability to comprehend and analyze complex situations, which can be relevant to the investigation. By evaluating the suspect's educational background, the detective can gain insights into the suspect's potential knowledge and motives related to the crime.