I have written a work of fiction about a serial killer. AT the end he is apprehended and there is irrefutable DNA evidence to his guilt. However, he does not want to be convicted unless he can take his accomplice with him. Would there be a trial if he admits to being guilty but claims he wasn't the mastermind? Would he still be tried if he was trying only to reduce his sentence from first degree murder to voluntary manslaughter? His accomplice claims she had no hand in the crime.