I understand this sentiment, honestly I do. But, stick with me here...
There is no end. Even if all life on earth ended today, that would not be the end. If the entire universe imploded, that would not be the end. So... If there is no end, then there can be no argument made to justify the means. And if nothing exists to justify the means; then the means are the only thing that matters.
It is "the means" that separates democracies from tyranny. It is the checks and balances in the leadership, it is the due process given to all persons, it is the simple idea that no man is greater than another and all are created equal. This is the very fabric of our society. And if we should discard these deeply held virtues simply for the sake of expedience then we are no different from any tyrant.
It has been said that freedom is only ever a day away from death. Do not ever let it die, simply for the sake of expedience. I would agree that expediting this man's trial might be what's "best for society. But I would argue that's what is "best" is not always what is right.