investigate
咨 centers on careful examination: investigating a matter by looking into it thoroughly. The given meaning is a single clear concept.
咨 combines 次 (next, order) with 口 (mouth), suggesting a structured verbal inquiry or investigation. The exact historical development is uncertain.
The top 次 suggests a sequence or step-by-step process, and the bottom 口 is a mouth asking questions. Picture a detective going through a list of questions, investigating step by step.
For シ, imagine a detective saying 'She' did it while investigating: 'She' -> シ, and the investigation points to her.