Investigative writing

As a writer, I feel I also try to include as much detail and description as I possibly can. While I have went about this writing style for an extended amount of time, investigative writing seems to be quite the opposite.
You are suppose to get right to the facts in a concise manner. You want to have just the basics in a report but, you also want to make sure you include all the essentials details, just with little opinions and vivid descriptions. Who, what, where, when, and why are main subtopics to answer when writing a report because this is essentially the most important part of the report.
I think of investigative writing as more complex then it really is, and hopefully I can reduce my word limit in future reports.