I was watching one of the typical installments this weekend (spouse dies of "accidental poisoning" and it's clear from the first minute of narration that it's murder and that the surviving spouse did the killing), when I heard a remarkable statement: "In Maryland, convictions may be had on circumstantial evidence, but Florida requires irrefutable scientific proof." Hogwash. Every state permits conviction of the direst crimes, including murder, on circumstantial evidence--and why not? Circumstantial evidence includes everything except eyewitness testimony--and eyewitness testimony is notoriously unreliable. Fingerprint evidence, fiber evidence, DNA evidence--all are highly reliable, though not "irrefutable," and all are circumstantial.
Why did the narrator intone that Florida requires "irrefutable scientific proof"? Because in the case under discussion, a trial judge (and trial-level decisions do not set precedent) refused to allow into evidence a report that potassium had been found in the victim's body. The judge refused to allow the report into evidence because potassium is found naturally in the human body, and the report did not show that the amount found in the victim was so abnormal as to be indicative of poisoning. The report, therefore, proved nothing, and should not have been admitted in any state--not because it wasn't "irrefutable," but because it didn't provide any evidence that there had been a murder.
Florida doesn't require "irrefutable" scientific evidence, and neither does any other state, because there is no such thing (think of the O.J. Simpson case). There is no evidence, scientific or otherwise, that cannot be refuted. Florida's busy death row includes many a murderer convicted on circumstantial evidence alone--be it scientific or not (and it need not be scientific).
So don't head for Florida if you plan to dispose of your spouse. And don't take weighty statements of the law on The New Detectives at face value. You're likely to get burned. Enjoy it for its formulaic, murder-will-out expositions only. It's all been done before, and done at least this well.
