I think the investigation actually would have begun a number of years ago. However, there are many investigations that are always going on within the department. This particular one involved a main group. There may be others who are tied to this, including people who have a presence in countries outside of India.
With respect to the people who may be involved, they could include all of the potential applicants who may or may not have known about the fraud. When you're asking what other fraudsters or bad actors we have discovered, there could be quite a significant range of people, depending on how broad a definition you take of “bad actor”.