At 10:40 a.m. on January 22, 1993, Mary Weaver, who earned a living as a babysitter, picked up 11-month-old Melissa Mathes at her parents’ home in Marshalltown, Iowa, and took the child to her home.
Less than 45 minutes later, Weaver, 41, called 911 because the child had stopped breathing on the living room floor. The child was revived and rushed to a hospital, but died the following day.
An autopsy showed that Melissa had sustained severe head injuries, including a massive skull fracture, sometime before her death. A fresh bruise on the front of her brain and new bleeding around the brain and in her eyes was also detected.
The doctors who examined the body opined that the older injuries were not the cause of death and that the more recent injuries showed she had been shaken to death. The cause of death was determined as Shaken Baby Syndrome.
Shaken Baby Syndrome (SBS), a term later coined for a condition first articulated in 1971, is said to describe a situation in which an infant is shaken so hard that the brain rotates inside the skull, causing severe and potentially deadly brain injury, but often without any external signs of harm. SBS is said to involve a tell-tale “triad” of symptoms – brain swelling, brain hemorrhaging and retinal hemorrhaging – which, when present in an infant who has no outward signs of abuse, indicate that the child has been violently shaken. According to received medical wisdom, no other injuries or pathologies could cause these three symptoms to occur at the same time, and – because it was believed that a victim of SBS became unresponsive immediately – the last person to have physical care of the baby must have caused the injuries.
On May 26, 1993, Weaver, a well-liked and deeply religious woman in Marshalltown, was charged with first-degree murder.
In her first trial, before a jury in Marshall County District Court, the evidence was hotly disputed and highly circumstantial.
The girl’s mother, Tessia Mathes, testified that on the morning Weaver picked up the child, Melissa had bumped her head on the padded footrest of a reclining chair, but did not appear injured.
Prosecution experts testified the earlier injuries were in the process of healing at the time of Melissa’s death and that the more recent injuries could only be explained by a violent shaking or slamming just prior to when she stopped breathing.
One prosecution expert said the more recent injuries were consistent with a fall from a three-story building. A defense expert characterized the injuries as similar to being swung by the ankles against a brick wall.
Defense experts testified there was no evidence showing Weaver had harmed Melissa and that the girl had already been critically injured and close to death when Weaver picked her up.
The defense called a cemetery worker to testify that the child’s mother had inquired about the cost of a grave site about a month before Melissa died. Tessia denied she had made such an inquiry.
The case ended in a mistrial when the jury could not agree on a verdict.
In March 1994, Weaver went on trial again, electing to have the case decided by Marshall County District Judge Carl Peterson, instead of a jury. The evidence was similar to the first trial, except that Peterson barred defense lawyers from introducing the testimony from the cemetery worker.
On March 22, 1994, Peterson found Weaver guilty, concluding that Weaver was alone with Melissa when the fatal injuries were inflicted.
Before sentencing, the defense filed a motion for a new trial, asserting that two new witnesses had come forward to say that Tessia told them that Melissa had hit her head on a table—not a padded footrest—before Weaver picked her up. Judge Peterson denied the motion for new trial, ruling that the testimony was inadmissible hearsay and even if admissible, would not have changed the verdict.
On May 3, 1994, Peterson sentenced Weaver to life in prison without parole.
The Iowa Court of Appeals upheld the conviction on September 22, 1995.
Weaver’s lawyers sought further review of the appellate decision, arguing they had discovered even more new evidence favorable to Weaver and the Iowa Supreme Court remanded the case for a hearing on a second motion for new trial.
At the hearing, conducted by Marshall County District Judge Allan Goode, affidavits from three more witnesses were presented—women who gathered regularly to have coffee in a Hardee’s restaurant in Marshalltown where Tessia Mathes worked as a waitress.
All three said Mathes told them Melissa had hit her head on a coffee table and two of the witnesses said Mathes told them the girl was knocked unconscious.
The defense also called a medical expert who had not testified at the trial, Dr. Brian Blackbourne, who testified that Melissa’s vulnerable neurological state on the morning she was picked up combined with the trauma described by the new witnesses offered a reasonable medical explanation for the acute conditions that precipitated the child’s death.
On January 31, 1996, Goode granted the motion for a new trial. Weaver was released on bond on March 20, 1996. The state appealed and on September 18, 1996, the decision was upheld by the Iowa Supreme Court.
In February 1997, Weaver went to trial for a third time and was allowed to present the new evidence. The jury acquitted Weaver on March 5, 1997.
– Maurice Possley