When Casey Anthony was acquitted of murdering her 2-year-old daughter, the verdict was widely denounced by law-’n’-order types. Having not paid any attention to the trial, I didn’t venture an opinion; at a glace, my best guess is that she probably did it in fact but that the jury didn’t see enough evidence to convict “beyond reasonable doubt.”

An essay by Marcia Clark, the prosecutor who bungled the O.J. Simpson trial made me wonder what they’re teaching in law schools or testing for on the bar exam: if “reasonable doubt” means anything, it must mean that there exists a coherent, reasonably plausible view of the evidence consistent with innocence. That is, if the jury has a reason to doubt guilt, the verdict must be not guilty. That wasn’t in fact true in the O.J. case, where a murderer skated because he hired a brilliant defense team and drew a lousy prosecutor and a lying investigator. But it seemed to be true of Casey Anthony.

That was then. This is now. And now we learn that a key piece of prosecution evidence – the claim that Anthony had done 84 computer searches for choloroform – was false, and known to be false by the prosecution a week before the case went to the jury, because a prosecution witness, the designer of the software on which the police testimony was based, had told the police and the prosecutor that the result in question was wrong.

That’s an outrage: it’s hard to imagine that the expert’s opinion didn’t constitute “exculpatory evidence,” and it’s an absolute rule that exculpatory evidence known to the prosecution must be disclosed to the defense. An even bigger outrage was this bit of slime-and-defend from the sheriff’s office:

Capt. Angelo Nieves, media relations commander for the Orange County Sheriff’s Office, said Mr. Bradley had a vested interest in coming forward since his software was used in the investigation.

“We’re not going to relive the trial again,” Captain Nieves said. “We are not prepared to do that nor are we going to participate in that.”

“Vested interest”? Huh? “Not going to relive the trial”? You mean, not going to review the gross misconduct of your organization which might have railroaded Caylee Anthony to the gas chamber?

Alas, courts have made police and prosecutors (and judges) immune from civil suit for cheating in the courtroom. And it’s possible that the passive refusal to accord a defendant her clear legal right to exculpatory evidence doesn’t actually constitute a crime. So the sheriff’s deputies involved will probably survive to cheat again, with no career damage at all. Ironically, since Anthony was acquitted, there’s no chance to use the appellate process to force the truth into the open. But if I were the prosecutor in this case, I’d be very, very worried about keeping my bar card.

Footnote And yes, she still probably did it. Her failure to call 9-1-1 after her child “disappeared” is pretty much a smoking gun. [Update: Unless what really happened was an accident followed by a cover-up.]

[Cross-posted at The Reality-Based Community]

Mark Kleiman

Mark Kleiman is a professor of public policy at the New York University Marron Institute.