Check this article, use Google translate if needed https://pt.wikipedia.org/wiki/Punhal_Verde_e_Amarelo

The Supreme Court in Brazil can be as rotten of political as it wants, to make a plan to assassinate political rivals is just completely unacceptable.

And before someone tries to defend the bolsonaros by saying they were not involved in this, don't use a defense that they themselves did not use. The defense that Flávio Bolsonaro said about the incident was "thinking of killing someone is not a crime".