When St. Louis Post-Dispatch reporters tried to track down a tip about a doctor who removed the wrong kidney from a patient, the journalists were surprised to find so little documentation. 

In this short piece, the journalists describe all the places they looked for information and note that all of them were dry holes -- which of course raises the question of why this information is so difficult to find.

Investigative reporter Jeremy Kohler looked at malpractice claims, looked for lawsuits, looked for disciplinary actions (state and federal sources). The hospital hid behind HIPAA laws.

Here's what I like about this article: For many of us, not finding the information would keep us from reporting the story, but Kohler made the problem the story. Smart.