Doubt isn't just a "bad feeling." It acts like a constant alarm: you interpret every delay, every silence, every detail. And the more you search alone, the more your imagination fills in the gaps.
Investigations are often associated with surveillance, fieldwork, and hours of observation. But in reality, the value of a mission lies primarily in the delivery : a clear, dated, structured report — and above all, one that can be used if proceedings are underway (or likely).