If Nero thinks Raposo is a rat and decides to kill him without knowing for sure. When he gets some disclosure from Crown Prosecutor after his is arrested and finds out there are really 5 rats maybe then he starts killing everybody around who doesn't go to jail at the same time as him?

Remember Nero got his start from robbing an armoured car and got 1 million dollar, This money is never recovered.

https://www.canlii.org/en/on/onsc/doc/2013/2013onsc7000/2013onsc7000.html?resultIndex=12

[15] The monies that he received from the armoured car heist of approximately one million dollars remain unrecovered. The position taken by G4S is that Nero is seeking to fund his defence with money that belongs to G4S.

Use stolen money to defend himself in court and then start a cocaine business. He is a funny guy but also litigious.