I personally know a person who was charged and convicted of the Crime of Libel (in what for my country was an incredibly speedy legal process) for accusing a local politician of Corruption.

Curiously, about a decade later said politician was convicted for Corruption. Lets just say it only happened because that Libel conviction really pissed of that person who had time, brains and no fear of their professional life being affected, so they worked tirelessly behind the curtains to push an earlier report into "irregularities" in his City Hall all the way into and as a case against him, including digging evidence even from abroad and having to threaten with exposure in the Press at least 3 public prosecutors who on different occasions were quietly holding the case so that it didn't get to court before the deadlines for prosecution expired (and even then that politician actually got away with a number of crimes because the deadlines for prosecution did expired for those). In fact that was the first politician ever in my country convicted of Corruption.

Libel having been made a Crime in my country (which is quite unusual in the World) was done exactly so that people can be punished for openly accusing the powerful of malfeasance without the powerful having to bare the costs for a civil court case and actually prove damages (so it mainly helps politicians in the big parties who have the connections to get the local Public Prosecutions Office to take the case to court) and that's exactly how it has been used.

By an amazing coincidence my country is one of the most corrupt countries in Europe and last I checked was the one most behind in implementing the EU advised anti-Corruption measures.