[music playing] NARRATOR: Four-month-old Ryan Stallings had spent an entire weekend vomiting. When he also developed breathing problems, his mother decided to take him to St. Louis Children's Hospital. [music playing, baby crying] Somewhere along the way, Patricia Stallings made the wrong turn and got lost. It was a mistake she'll regret for the rest of her life. [music playing] Patricia and David Stallings had been married for about a year and had recently moved into a home overlooking Lake Wauwanoka just outside of St. Louis, Missouri. David was a printer. Patricia worked in a convenience store. Four-month-old Ryan was their only child and had always been sickly. After an entire weekend of vomiting and breathing problems, Patricia decided to take the baby to St. Louis Children's Hospital. During the trip, Patricia got lost and ended up at the emergency room of Cardinal Glennon Children's Hospital instead. Doctors there perform tests to understand what was causing Ryan's illness. He was listless, almost comatose, and continued to vomit. Nurse, let's get that blood right away. NARRATOR: He was given a complete medical examination, including blood and urine tests. Ryan's blood samples were sent for testing to an outside, independent lab, the SmithKline Beecham Clinical Lab in St. Louis. Gas chromatography on Ryan's blood sample found the cause of the child's illness. It was ethylene glycol poisoning. Ethylene glycol is a colorless, sweet-tasting substance found in industrial solvents and resins. It can be fatal in large enough doses. Hospital officials notified both the sheriff's department and the Missouri Department of Family Services. I'll take the basement. NARRATOR: Investigators searched the Stallings' home. In the basement, they found two containers of antifreeze under a pool table. One of the containers was half empty, and it listed ethylene glycol as the main ingredient. You cannot form ethylene glycol in your body. The body can naturally form that. Therefore, it has to be ingested. And when you've got a child who's four months old, a child who's four months old doesn't have the capability of ingesting anything, therefore, it had to be purposefully ingested. NARRATOR: Fortunately, Ryan's condition gradually improved. When he was released from the hospital, he was not returned to his parents. Instead, the Department of Family Services placed Ryan in foster care until they completed their investigation. And that investigation revealed some troubling information. They discovered that Patricia Stallings was the mother of another child, a five year old son who was in her sister's custody because of allegations of child abuse. He was born out of wedlock when she was young. Subsequent to his birth, he was taken away from her by the state when they discovered that he was in the first stages of frostbite and malnutrition. Now, Patricia's explanation to me at the time was that, you know, the reason that he was in that state was because she was in a similar state because she didn't have any money, any place to live. NARRATOR: While Ryan was in foster care, Patricia was only permitted to visit him once a week under the supervision of the Department of Family Services, or DFS. A few days after her sixth parental visit, Ryan got sick once again and was taken to Cardinal Glennon Children's Hospital. This time, the lab found even higher levels of ethylene glycol in Ryan's blood, 911 milligrams per milliliter of blood serum. Ryan's blood was also sent to the toxicology lab at the University of St. Louis. They performed another test called mass spectrometry that found the same thing, ethylene glycol in Ryan's blood. Although the baby bottle Patricia used to feed Ryan during her supervised visit had been washed and refilled, tests on that bottle found trace amounts of ethylene glycol. And prosecutors learned that the individual assigned to stand guard during Patricia's visit with Ryan inexplicably left the room for a short time against instructions. Prosecutors suspected that Patricia had poisoned Ryan again after the supervisor left the room. We went over in detail talking to every person that was there in the room, every movement that was in the room, what things were brought into the room, the bottle seized from the visit, again, tested positive for ethylene glycol. NARRATOR: Patricia Stallings was arrested and charged with assault. Is That the ethanol drip? Yes, it is. Get that in right away. NARRATOR: When Ryan was diagnosed with ethylene glycol poisoning, his treatment included both fasting and ethanol given intravenously to counteract the effects of the ethylene glycol. One week later, Ryan Stallings died. The charge against Patricia Stallings was now murder. When four-month-old Ryan Stallings died, a social worker from Cardinal Glennon Children's Hospital called Patricia Stallings in prison to inform her of her son's death. I don't care about that. Put David on the phone. I want to get out of this hellhole. NARRATOR: Patricia's response raised suspicions. When you put those kinds of statements and the reactions and all the things and the circumstantial evidence together with the science, it only pointed to one person. NARRATOR: Laboratory tests revealed large amounts of ethylene glycol in Ryan's blood. Ethylene glycol is the main ingredient in antifreeze. Scientists also found trace amounts of ethylene glycol in the baby bottle Patricia Stallings used to feed Ryan during her last visit. Three months later, while still in prison awaiting trial, Patricia Stallings learned some surprising news. She was pregnant. During her pregnancy, Patricia became friends with prison guard Patty Matthews. She was very depressed most of the time. You know, she'd been through a lot. And it was just a-- an amazing emotional strain that she was going through. NARRATOR: Five months after Ryan's death, Patricia Stallings gave birth to David Stallings Jr. in a hospital near the prison. Patricia and David nicknamed him DJ. When DJ was just a few weeks old, he had an episode of vomiting, seizures, and breathing problems while in foster care. DJ was rushed to St. Louis Children's Hospital. Ironically, it was the hospital Patricia planned to take Ryan to before she got lost. Doctors diagnosed DJ with a very rare metabolic disorder called methylmalonic acidemia, or MMA, which inhibits the body's ability to process food, especially proteins. It also produces toxins in the blood. To prosecutors, it was a startling development. They wondered if Ryan Stallings might have died of the same disease instead of ethylene glycol poisoning. We went back to square one. Met again with all the doctors and said, look, something's not right here. And matter of fact, released her from custody at that point on a recongizance bond, which is unheard of in a murder case. NARRATOR: But the prosecution's medical experts did not believe that Ryan died of MMA. His blood had been tested at two independent laboratories. Both found ethylene glycol in Ryan's system. And the autopsy revealed calcium oxalate crystals in Ryan's brain, consistent with ethylene glycol poisoning. Tests on Ryan's baby bottle also found trace amounts of ethylene glycol. Everyone was saying there was ethylene glycol in the body. Tests from different laboratories showed that. And everyone agreed that if there's ethylene glycol in the body, it wasn't MMA that killed the child. NARRATOR: So the murder case against Patricia Stallings went to trial. Prosecutors were seeking the death penalty. Despite the genetic illness diagnosed in DJ, Patricia Stallings' defense attorney could not produce one medical expert to testify that it was MMA and not antifreeze poisoning that caused Ryan's death. I put on my witnesses, all of them said ethylene glycol, all of them said it had to be ingested, all the evidence pointed toward Patty Stallings. If somebody fed the baby antifreeze, it must have been her. NARRATOR: The jury also heard what Patricia Stallings said to the social worker when informed of Ryan's death. Patricia Stallings was found guilty of murder in the first degree and was sentenced to life in prison without possibility of parole. Her husband, David, collapsed in shock after hearing the verdict and was rushed to the hospital. She was just devastated. She was very upset. She was crying. We talked for a little while. There wasn't a whole lot of comfort I could offer at that point. NARRATOR: Although the jury had reached its verdict beyond a reasonable doubt, two local scientists had doubts of their own. Although Patricia Stallings was found guilty of the poisoning death of her son Ryan with antifreeze, not everyone was convinced. Dr. William Sly and Dr. James Shoemaker wondered whether the lab tests done by their colleagues and by the SmithKline Beecham lab were accurate. JAMES SHOEMAKER: It was only when I found out that no one had really thoroughly explored the science behind the ethylene glycol testing that I became convinced that I had to do it myself. NARRATOR: First, Dr. Shoemaker turned his attention to the gas chromatography used to test Ryan's blood. In gas chromatography, the sample is vaporized and sent down a tube with an inert gas. Each compound settles in the tube at a different rate, which is called the retention time. Those retention times are then charted on a graph. A reference library of retention times is then consulted in order to identify any compounds found in the blood. Medical experts who testified against Patricia Stallings said that the peak on the graph of Ryan's blood serum appeared at a retention time that matched that of ethylene glycol. Dr. Shoemaker retested Ryan's blood samples and analyzed the retention times. He didn't find ethylene glycol. He found something else. There was a compound that was very highly elevated in the serum, compound called propionic acid, that comes off very close, but not identically with ethylene glycol. And he and I speculated that that might be the-- the basis of a misidentification that led to the incorrect diagnosis of ethylene glycol poisoning. NARRATOR: Proprionic acid is often produced in patients who have MMA, the rare genetic illness diagnosed in Ryan's brother, DJ. The only difference between propionic acid and ethylene glycol is a few carbon atoms. To find out if other labs were capable of misreading propionic acid as ethylene glycol, Dr. shoemaker sent blood samples spiked with propionic acid to seven different laboratories. Sure enough, three out of the seven laboratories that we tested came back with positive results for ethylene glycol when we knew the only thing in those samples was propionic acid. NARRATOR: When Dr. Shoemaker examined the graph shown to the jury during Patricia Stallings' trial, one showing the ethylene glycol found in Ryan's blood, and next to it, a graph of a known sample of ethylene glycol, he discovered a huge mistake. But the tragic thing is that no one bothered to actually superimpose the two like this. And when you look at it very closely and line up the injection point here and the internal standard here, the two pigs are actually quite different. And you move them up here so you can see, they don't come out at the same time at all. The retention times are actually very different. NARRATOR: Dr. Shoemaker suspected that Ryan Stallings died of MMA and had not been poisoned with ethylene glycol. But Dr. Shoemaker was a junior member of the faculty at the time and knew that his conclusions would be challenged by experts. When prosecutors learned about these new test results, they were stunned. Was it possible that Patricia Stallings had been convicted of a murder that never happened? The Stallings hired attorney Robert Ritter to handle their appeal. He immediately requested a new trial, arguing that Patricia Stallings' first lawyer had not mounted a proper scientific defense. After several hours of discussion, I came away convinced that Patty did not poison her child and that a horrible injustice had resulted here. NARRATOR: When prosecutors heard the new test results from St. Louis University, even they agreed that this new medical information raised serious questions. Once we were well aware that there were actually doctors out there prepared to say that, that, obviously, didn't testify at trial, may have made a difference at the trial, and we agreed to a new trial, and we didn't have to do that. NARRATOR: But prosecutors had two independent laboratories that found ethylene glycol in Ryan's blood. Traces of ethylene glycol were found in the baby bottle. And the autopsy report found oxalate crystals in Ryan's brain, a finding consistent with ethylene glycol poisoning. To sort through the scientific inconsistencies, prosecutors sought an outside expert. At Yale University, they found Dr. Piero Ronaldo, one of the world's leading experts in metabolic diseases. He reviewed the scientific data that formed the basis for the case against Patricia Stallings. I received all the raw material, all the data from the labs where the tests were done. That was really the exceptional moment for me in this story because I couldn't believe how low was the quality of analytical work done in the commercial lab. NARRATOR: Dr. Ronaldo called the lab reports garbage. He agreed with Dr. Shoemaker and Sly that the gas chromatography peak shown to the jury as that of ethylene glycol was not ethylene glycol at all and did not match the graph depicting the known sample of ethylene glycol. The retention time of the peak in question was 33 seconds later, which, in gas chromatography, is an enormous difference. It's-- it's really huge. NARRATOR: And when Dr. Ronaldo reviewed the mass spectrometry results, he found a similar error. The spike in Ryan's blood identified as ethylene glycol did not match the known sample. That really blew me away because, especially in a case where, obviously, with legal implications, it must be perfect match. This was not even close. It was, again, absolutely strikingly obvious evidence that there was no match. NARRATOR: Dr. Ronaldo immediately presented his findings to prosecutor George McElroy the next day, McElroy held a news conference. State of Missouri is dismissing all pending charges against Patricia Stallings based upon the death of her child, Ryan. And I'm satisfied, I'm convinced that Patricia Stallings did not poison her child. NARRATOR: Dr. Ronaldo believes that Ryan Stallings died of MMA, the same genetic illness his brother DJ was born with. Is that the ethanol drip? Yes, it is. Let's get that in right away. NARRATOR: He also believes that the inaccurate lab reports led doctors to administer the wrong treatment, the ethanol drip, which possibly contributed to Ryan's death. The ethanol drip was also the suspected cause of the calcium oxalate crystals found during Ryan's autopsy and not ethylene glycol. Scientists also suspect that the process of washing Ryan's baby bottle caused the false readings of ethylene glycol when the bottle was tested. The conviction of Patricia Stallings had been a mistake. Oh, wow, if DJ hadn't been born, Patty Stallings would be in jail for the rest of her life without parole and no one would ever have raised a second question. I think DJ-- DJ's birth is what saved her because it-- the first child's diagnosis would never have been made. I can understand a person who's been through all that she went through finding the-- an apology pretty lacking. But as I told her, I-- I had a job to do. I had the evidence before me that I felt gave me no choice. NARRATOR: Patricia Stallings filed lawsuits against the hospitals, doctors, and laboratories that had misdiagnosed Ryan. All were settled before going to trial. Their son, DJ, who by being born with MMA, led scientists to the real killer of his brother, Ryan, is managing his disease with a special diet and other treatments. It is strange that such a small mistake on paper could make such a huge change in the lives of people. But in this case, you can see that a few millimeters of difference in where a peek appeared on a sheet of paper made all the difference in a woman's life. The science was the strongest evidence and was what ultimately convicted her, but it was also what ultimately freed her. [music playing]