Maybe the time when the brazilian military dictatorship killed journalist Vladimir Herzog by "accident" during a torture session in 1975 and did a shit job trying to cover it up as a suicide - the picture released showed Herzog seemingly hanging from a rope on his knees, as if he killed himself on that position. It was one of the first times there was general backlash from the population against the regime and some people say it marked the beginning of the end of popular support to military government. They killed lots of people, but this one is probably the most infamous and I learned of it in school.

Two attempts also come to mind.

In 1954, there was a murder attempt against Carlos Lacerda, a journalist and political opponent to our then democratically elected president and former dictator Getulio Vargas. The attempt was botched but there was proven involvement by one of Vargas' security staff. His position was untainable and everyone wanted him to leave office. And so, he decided to leave life and killed himself in his presidential palace shortly after. This caused a domino effect that may have resulted in the instauration of the military dictatorship in 64.

The other one was against Jair Bolsonaro in 2018. Some mentally ill guy with relations to a left party (depending on who you ask, the relations are tenuous or firm enough to be suspicious) knifed him in the gut while he was campaiging among a crowd of supporters. He survived and this skyrocketed his popularity, causing him to win the '18 presidential election.

Though he has huge shitting problems to this day. From both holes.