[danielweber]

so there can be a single trial in which the truth comes out.

As a point of order, since trials are incredibly stressful and expensive for the accused, society isn't supposed to use them for "the truth to come out" or "to find out what happened."

The trial is where the state -- having decided internally that a person is guilty and must be punished -- goes to prove its case to a jury of the accused's peers, in an orderly courtroom where only pertinent evidence is allowed.

This probably backs up your point even more -- having multiple trials for the same thing is horrible for the accused.