She gently turned Dillon over on his back to change the diaper.
To her horror, the infant was ashen, cool to the touch.
Lisa Randall (in jail clothes) and her supporters listen as her attorney, David Cantor, speaks on her behalf in an early 2008 hearing.
Prosecutor Jeanette Gallagher argues at the same hearing to keep Randall behind bars.
Lisa briefly tickled his feet trying to rouse him, but Dillon remained unresponsive.
She had been around children her entire adult life as a mother, grandmother, kindergarten teacher, and daycare operator, and had dealt with the array of typical childhood bumps and bruises.
But nothing even close to this had ever happened on her watch, an infant who wasn't breathing and appeared at death's door.
Lisa picked up Dillon and rushed him to the kitchen, breathing into his mouth as she dialed 911.
"Help me! Help me! Oh, my God!" she screamed into the phone. "I don't know why he stopped breathing! Help me! Help me!"
Peoria police later alleged that Lisa said during the 911 call, "What did I do?" which suggested to them an admission of criminal responsibility.
But even after repeated listens, a county judge determined it is very difficult to say for sure what words Lisa had shrieked: She may well have cried out, "What do I do?" referring to her ongoing resuscitation efforts. (Even if Lisa Randall did use the past tense, it sounded more like a plaintive wail than any kind of confession.)
Emergency personnel rushed Dillon to Banner Thunderbird Medical Center, about four miles from Lisa's home.
Doctors there got Dillon's heart going again, but his condition was critical, his brain deprived of oxygen for precious untold minutes.
A CT scan of Dillon's head at Banner Thunderbird showed "no acute findings," nor any "evidence of intracranial hemorrhaging" — nothing that immediately suggested possible child abuse.
Dillon remained at Banner Thunderbird for about an hour before he was taken by helicopter to Phoenix Children's Hospital and its sophisticated pediatric intensive-care unit.
Subsequent testing at Phoenix Children's revealed Dillon was bleeding inside the protective layers of his brain, which was badly swollen. (When excess fluid enters the skull, it may cause the brain to dangerously swell and slosh around as the flow of blood to the brain decreases. Causes of such swelling, according to the Merck Manual medical library, are myriad.)
Tellingly for doctors at Phoenix Children's, the retinas in Dillon's eyes showed distinct signs of hemorrhaging. (The retina is light-sensitive nerve tissue at the back of the eye. It may bleed when tiny vessels on its surface rupture, sometimes after an incident of violent shaking or another injury.)
Doctors eventually detected what they suspected were two small fractures of Dillon's skull, including one "depressed" fracture that suggested a blunt-force injury of some kind.
Remarkably, though, they found no external sign of injury to the infant's head — nary a bruise, bump, or scrape.
According to the medical literature read by New Times, skull fractures occur only when a child's head makes profound contact with an object — a floor, a wall, a fist.
"When you see bruises, you have to start thinking that there's something else going on," Dr. David Posey, a pathologist hired by the Randalls, testified later during a court hearing. "There's absolutely nothing there at all."
Doctors in child-abuse cases involving brain damage often uncover injuries to the body indicative of apparently intentional wrongdoing, including damage to the arms, ribs, abdomen, or legs sustained during an assault.
But Dillon had suffered no injuries to his body that could be attributed to abuse.
Still, within a few hours of Dillon's arrival at Phoenix Children's, his treating physician had seen enough evidence to tell a Phoenix police detective that it looked to him like a "pretty classic" case of child abuse.
Dr. Adam Schwartz was referring to what is widely known as "shaken baby syndrome" and to the presence of the supposedly ironclad diagnostic "triad" said by many (not all) medical specialists to point to child abuse: brain bleeding and swelling, plus retinal hemorrhaging. (The Child Welfare Information Gateway, a federal Web site, estimates that 1,200-1,400 children suffer from shaken baby syndrome each year in the United States, with a mortality rate of about 30 percent.)
Dr. Jennifer Geyer, a forensic pediatrician at the hospital, quickly concluded that Dillon's injuries definitely were inflicted during his one hour at Randall's home. The baby would have deteriorated almost immediately after suffering brain trauma, she told Detective Robert Webber that day.
That timing would become a linchpin of the case that Peoria police immediately began to try to build against babysitter Lisa Randall. But, much later, it and everything else in this tragic case would come under serious scrutiny, especially after specifics and ranges of possible causes for Dillon's brain and retinal damage came to light.
Late that afternoon, Detective Webber asked Dr. Jerald Underdahl, an ophthalmologist at Phoenix Children's, whether Dillon's retinal hemorrhages were consistent with a punch or impact with enough force to crush a skull.
Absolutely, the doctor replied, according to Webber's report.
But Underdahl also said Dillon's retinal injuries could be up to two days old, a key observation that would get short shrift by authorities in what later became a first-degree murder case.
If the doctor was correct, Lisa Randall's attorney would allege, the retinal damage might not have been inflicted during the fateful hour at Randall's home, if it actually was inflicted at all.