Good Investigative reporters are like Detectives in that they must uncover and verify the truth of the situation they are investigating.
And no matter what they uncover, there is a separate “confidence level” required to meet in judgement of the accuracy and completeness of what they plan to put into print.
As a result, a “good story” will not be published because the editorial standards of the organization may have a single source that wishes not to be identified publicly.
The editors of the more unbiased and more professional news organizations will likely require that info to be published – have multiple sources that are saying almost exactly the same story, and that the reliability of one or more of these sources has been, in the past, without problem ( what they have said in the past has not been contradicted by any believable evidence).
So, if these “Good” organizations are careful to carefully confirm facts and vet sources (sources can have their own motivations to tell a non-truthful story) , and do not allow personal bias to interfere with shining a strong light into ALL the corners of the story, then this story, having been confirmed to good journalistic standards of accuracy, honesty, and completeness, may then be published.
Or did you think the reporter simply sits in a room and uses his or her imagination? NO. Journalism schools in America, as well as the top level news organizations teach them how to verify sources, dig deep into public records, and how not to be caught with a biased or partially true story.
A organization gathers “trust points” over time, by reporting a story accurately and in depth, with as little mistakes as possible. And when a mistake is made, the organization will reprimand, demote, punish, and fire the reporter responsible for writing something not up to a high standard of Journalism. And it must do this promptly, without external pressure and in a transparent manner, and also to print a visible and clear retraction/correction of the facts. You can see this in the track record of sites like CNN, NBC, WSJ. Yes, they make mistakes, but they take quick action, are transparent about punishments and blame, and they apologize – sincerely.