01/03/2012 05:36 pm ET Updated Jan 04, 2012

Hannah Overton's Conviction Of Murder Salt Poisoning Gets New Scrutiny

In 2007, 30-year-old mother of five Hannah Overton, a devout Christian, was convicted of murdering her four-year-old adopted son Andrew. The cause of death was salt poisoning, a rare but fatal condition caused by ingestion of more sodium that the body can process. Prosecutors in the case, which was covered breathlessly by local and national media, said that Overton had force-fed her son dried soup in a deliberate effort to kill him.

Overton denied the charges, and some of the evidence against her was suspect even at the time of the trial. But the case against her was enough to convince jurors that, even if Overton hadn't meant to kill Andrew when she fed him the soup powder, she deliberately caused his death by failing to promptly call an ambulance when he started to fall ill. She was convicted of "capital murder by omission" and sentenced to a life in jail without the possibility of parole. She maintained her innocence, but lost several court appeals over the following years. Her case looked hopeless.

Over the past few months, though, new medical evidence has provided the best case yet for Overton's innocence of the gruesome crime she's been convicted of. Back in April, John MacCormack of the San Antonio Express-News wrote :

"Most striking, evidence discovered in the prosecution files reveals that Andy's stomach contents (of salt) when he arrived at Driscoll Urgent Care was a low 48, as shown in a test of gastric content from the hospital," asserted Cynthia Orr, Overton's lawyer.

This new evidence convinced some medical experts that Andrew, whose history of eating-disordered behavior was obfuscated in court, had eaten too much sodium himself. And crucially, the low concentration of sodium in Andrew's stomach meant that no action on Overton's part could have saved his life. It was enough to convince Orr to file a writ of habeas corpus in a last-ditch effort to overturn what many now see as Overton's wrongful conviction.

And this month, in a long, fantastic piece on the case, Pamela Colloff of Texas Monthly tries to convey the entire Overton story as it actually happened. Colloff's account is reminiscent of David Grann's harrowing 2009 New Yorker investigation of the wrongful execution of Cameron Todd Willingham. It unpacks the layers of distortion that clouded the initial ruling and explains, with utter clarity, the importance of the new evidence. The feature ends with a solemn scene of bedtime prayer at the Overton household:

“Dear God, thank you for the soup,” Isaac said, his head bowed, his eyes closed tightly. “And thanks for the movie, even though it was kind of weird. I pray that you will bring Mom home soon.

But there's a lot more to the case than that -- so be sure to read the feature in full online here or in the January 2012 issue of Texas Monthly.