Kinds of story
Investigative journalism
Also: investigative reporting
In-depth reporting that digs out information someone wants hidden, usually exposing wrongdoing in the public interest.
Investigative journalism is the slow, hard end of the trade: months of documents, sources and dead ends to stand up something that matters. It leans on leaks, freedom of information and patient interviewing, and it lives or dies on accuracy, because the targets can afford lawyers. It is also where the press does its most important public work.