A couple of weeks ago, TV Globo ran a story linking President Jair Bolsonaro to the murder of Rio City Councilor Marielle Franco. The very next morning, a prosecutor involved in the probe held a press conference to say that the story was based on a false testimony given to the police—and that the president had nothing to do with the case. Soon, however, left-wing outlets dug up pictures of the prosecutor published on social media, showing her fervent support for Mr. Bolsonaro—and disdain for the Workers’ Party.
The prosecutor was quickly removed from the case, but this...
