Yeah, that's probably the embassy that got in touch with the FBI to get more information from winners about agents. From the reports, it seems agent problems in that particular country got so endemic that the embassy had to step in (I don't think it was from individual reports, probably through a local investigation), which is very rare and borderline exceptional.
Most of reports we hear about where embassies engage local law enforcement is when they can see that the applicant is involved and knowingly participating in visa fraud by misrepresenting documents (marriage , etc)
But I personally think dealing with this problem by waiting for victims complaints and then acting on individual cases is just a drop in the ocean. Besides very few people will be lucky enough to discover they got cheated by agents (or may be discover the truth too late) and have material proof that could build a compelling case if reported to the embassy. Agents are also getting smarter everyday, I don't think they reveal their real names etc to clients.
The DoS has brought in technical innovations to reduce fraud to some extent, but this problem has tagged along the DV program for years, and apparently only a radical innovation will make it go away for good.
I also think embassies that really want to deal with the problem should step in and tackle the source of the problem: information&communication.
From what I have seen so far, agents' public relations and communication/advertising tools are way more effective and aggressive than what embassies do to warn people. So efficient are agents' PR and communication that I suspect most applicants genuinely believe agents are the only official way the lottery is run. As the saying goes, Don't do the same thing over and over again and expect different results. Somehow the embassies' warning message against agents just doesn't reach enough people to effectively curb the agent problem(why? Embassies should find that out, they're supposed to know their areas really well), may be embassies should look for another way to up their game in this context? But again, may be that's asking too much from them. Meanwhile, the problem will unfortunately continue to worsen with time as agents do constantly improve their tricks ("quality improvement" seems to be something agents take quite seriously
).