To determine the method used for identifying the presence of semen in forensic investigations, we need to focus on the context provided: the appearance of yellow iodine crystals with picric acid. This description is crucial in identifying the correct test.
The question provides various options, and the choice must align with the specific chemical reaction involving iodine and picric acid. Among the listed tests, the correct answer is:
Barberio’s test
Explanation: Barberio’s test is a forensic method used to detect sperm through the formation of characteristic yellow crystals when iodine is introduced to picric acid. This test is particularly relevant when investigating cases of sexual assault, as in the scenario described.