There's an article on the internet written about how to write a report of an investigation.
However, I'm a bit confused of the usage of "investigation" and "investigative" in the article.
The link of the article is here: https://i-sight.com/resources/ultimate-guide-to-writing-investigation-reports/
In that article, they call it "Investigation reports" in the title, but they use "Investigative report" in the body of the article, instead.
I don't know whether this sort of usage is their mistake or it's grammatically correct. If they're absolutely correct, please explain to me the difference between "Investigation report" and "Investigative report".
And a side question, can I use "Investigating report"?