actually in the courtroom with him, speaking to the jury. 4-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. 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. patricia and david stallings had been married for about a

year and had recently moved into a home overlooking a lake just outside st. louis, missouri. david was a printer. patricia worked in a convenience store. 4-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 performed 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 way. >> he was given a complete

medical examination, including blood and urine tests. ryan's blood samples were sent for testing to an outside lab, the smithkline beecham 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 colors 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. >> 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 cannot naturally form that. therefore it has to be ingested. and when you have a child that's 4 months old, a child that's 4 months old doesn't have the capability of ingesting anything. therefore it had to be purposefully ingested. >> 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 5-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, the reason he was in that state was because she was in a similar state. she didn't have any money for a place to live. >> 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 the 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 and

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 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. patricia stallings was arrested and charged with assault. when ryan was diagnosed with ethenol 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 now was murder. [vet] two yearly physicals down.

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when 4-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. >> her response raised suspicions. >> i don't care about that. put david on the phone. i want to get out of this hell hole. >> when you put those kind of statements and the reactions and all the things and the circumstantial evidence together with the science it only pointed to one person. >> 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 had been through a lot. and it was just an amazing emotional strain that she was going through. >> 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 d.j. when d.j. was just a few months old, he had an episode of vomiting, seizures, and breathing problems while in foster care.

d.j. 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 d.j. 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. matter of fact, released her from custody at that point on a recognizance bond, which is unheard of in a murder case. >> but the prosecution's medical experts did not believe that ryan died of mma.

his blood has been tested at two independent laboratories. both found ethylene glycol in ryan's system. and the autopsy revealed calcium oxalate crystals in ryan's brian, 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 if there's ethylene glycol in the body, it wasn't mma that killed the child. >> so the murder case against patricia stallings went to trial. prosecutors were seeking the death penalty. despite the genetic illness diagnosed in d.j., 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 of the evidence pointed toward patty stallings. if somebody fed the baby antifreeze, it must have been her. >> 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. >> although the jury had reached its verdict beyond a reasonable doubt, two local scientists had doubts of their own. ;ñ;ñ;ñ

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. >> it was only when i found out no one had really thoroughly explored the science behind the ethylene glycol test that i

became convinced that i had to do it myself. >> first, dr. shoemaker turned his attention to 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. it comes off very close but not identically with ethylene glycol. he and i speculated that that might be the basis of a misidentification that led to the incorrect diagnosis of ethylene glycol poisoning. >> propionic acid is often produced in patients who have mma, the rare genetic illness diagnosed in ryan's brother d.j. 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 we tested came back with positive results for ethylene glycol. but we knew the only thing in those samples was propionic acid. >> 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 peaks 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. >> 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 your credit is in pretty good shape. >>pretty good? i know i have a 798 fico score, thanks to the tools and help on experian.com. kaboom... well, i just have a few other questions. >>chuck, the only other question you need to ask is, "what else can you do for me?" i'll just take a water... get your credit swagger on. become a member of experian credit tracker and find out your fico score powered by experian. fico scores are used in 90% of credit decisions.

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. >> 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 aware that there were doctors out there prepared to say that that obviously didn't testify at trial, it may have made a difference at the trial. and we agreed to a new trial. and we didn't have to do that. >> 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 accident with ethylene glycol poisoning. to sort through the scientific inconsistencies, prosecutors sought an outside expert. at yale university, they found a doctor, 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 the exceptional moment for me in this story, because i couldn't believe how low was the quality was of analytical work done in the commercial lab. >> dr. rinaldo 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@lean glycol at all and did not match the graph depicting the known sample of@lean glycol. >> the retention time of the peak in question was 33 seconds later. which in gas chromatography is an enormous difference. >> and when dr. win oldo 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. especially in a case 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. >> dr. rinaldo immediately presented his findings to prosecutor george mcelroy. the next day mcelroy held a news conference. >> the 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. >> dr. rinaldo believes that ryan stallings died of mma. the same genetic illness his brother d.j. was born with. 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 d.j. hadn't been born, patty stallings would be in jail for the rest of her life without parole and no one would have ever raised a second question. >> patricia stallings filed lawsuits against the hospitals doctors and laboratories that had misdiagnosed ryan. all were settled before going to trial. their son d.j., 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 peak 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. early monday morning on october 19, 1992, 23-year-old laura houghteling was seen leaving her bethesda, maryland home, walking to the train station on her way to work. she never arrived. a clue to her disappearance was a peculiar strand of hair found in her hair brush. laura houghteling was an ambitious young woman with a bright future. she had recently graduated from harvard university and had mov