In most investigations, interrogations are conducted with a clear and practical objective: establish the role of the individual sitting across the table.
Who were they?
What did they do?
Who helped them?
The focus is necessary, but it comes with a limitation.
Criminal networks are rarely exposed in a single interrogation because they are not designed to be visible end-to-end. Organised crime survives by fragmentation. Tasks are distributed. Roles are compartmentalised. Individuals know only what they need to know.