You as a prosecutor

You have the option to prosecute a criminal for the rape of a woman. There’s a plea deal though. This criminal has a pill that can cure any form of cancer. He has made a deal to let him go and he will release the secret recipe for this pill to the medical community. He must be charged with zero crimes. The entire public will know that you made a deal with the criminal and that is why the criminal walks free. The entire public will never know what the actual deal was though. Do you let the criminal walks free and end cancer or continue with the sentencing?