Further developing admissions
It’s safe to say that your subject knows more about what they did than you do; because they are the one that did it.
Understanding that principle should encourage you to further develop information from your subject and explore what is not known at this point of your investigation.
In the development phase we want to expand on admissions and work towards full disclosure. In other words, explore the unknown. One way to accomplish this is to make educated guesses about what else they could be taking based on the initial admission.
Making educated guesses is simple. For example, if someone steals a fishing pole you should consider accessories like tackle, lures, lines. If someone steals an iPod you should ask about cases, headphones, chargers, adapters. If someone is taking common booster items like baby formula, you should explore the possibility of other booster items like razor blades.
While exploring these educated guesses, evaluate the behaviour displayed by the subject to determine the truthfulness of their statements. Using the tactic of making educated guesses, you give yourself the opportunity to get closer to the true scope of their involvement.