We take for granted in the United States that an adversarial justice system is likely to produce the best results. But I think you demonstrate here why that can often not be the case.

In countries like France, where the criminal justice system is based on the Napoleonic Code, magistrates act as judges and prosecutors (procurators), and are charged with discovering the truth, not with conducting a vigorous, adversarial prosecution.

Well that system is no more perfect than the one we have here, many believe it is more apt to lead to justice.