What Do Investigative Reporters Do?

With the recent Chen Yongzhou scandal, many have called for an "investigation" into the investigative reporting business. 

I apply the term investigative reporters to those that often wade into the deeper, uncharted waters of the media's realm. I have a hard time thinking of myself as an investigative reporter and I've always felt like a more appropriate description would be a reporter that investigates cases from time to time. The first of my investigations was the Wenzhou high-speed train crash.