The case of Camm had sufficient evidence to warrant three separate trials in a very short space of time
Short space of time = 13 years? That's the amount of time in total that Camm was in prison.
Camm was finally found to be innocent of the crime he was said to have committed.
That's false. You are not understanding the legal language and legal concepts of the U.S. One can be only declared by a jury "guilty" or "not guilty," and that's it. There is no declaration of "innocent" by a jury, ever. And the reason is that absolute innocence (i.e. factual innocence) is not something any jury can know for certain. This is an important distinction. However, the US Constitution protects defendants from being tried twice for the same crime and once a "not guilty" verdict is reached, that's it, game over. The person can never again be tried by the state for that same crime.
There are many people who a jury acquits with a "not guilty" verdict (like OJ Simpson) but that doesn't mean the person did not actually commit the crime. It means the state, who always has the burden of proof in every criminal case, did not prove guilt beyond a reasonable doubt to
that jury. And the reverse is true as well--there have been people who were actually innocent and yet convicted by their jury. Fortunately, most of the time, juries get it right.
In the Camm case 2 different juries, under 2 different prosecutors, years apart, came to the same conclusion -- guilty. The convictions in each of those two cases were ultimately overturned on appeal. In the final and 3rd trial, evidence that was available to the juries in the first 2 trials was not part of the last trial (due to defense measures on appeal and motions), and a 3rd jury made a different decision.
Many people believe Camm is factually innocent. And many people believe Camm was involved or committed the murders himself and now managed to get away with it. But Camm is free and that's that. He could still be held responsible in a U.S. civil court and he is facing that in the future. But his penalty there would be financial, not imprisonment, and civil cases are brought forth by private parties, not the government.
And...
In Darlie's case, there has not been any overturn on appeal of her conviction. It's been 15+ years now and Darlie's appellate defense attorneys have taken her case through the various courts. She's running out of options for appeals.