100% of 2 Pros
Detectives come with a background in patrol work. Kind of a been there seen it. There is a lot of time spent for lack of a better word, investigating. Looking at reports, interviewing people, and more.
A lot of follow up to crimes that occurred while you were off duty , cold cases or brought to your attention by a Patrol officer. Reports writing, interviews and returning to the scene of the crime for possible new evidence, speaking with neighbors or witnesses .