Eleven-month-old Connor Robison died of blunt force trauma because of a fall from his playpen with his injuries exacerbated by CPR efforts to save his life, a medical expert testifying for the defense opined Monday in the murder trial of Michael Tahtinen.
Tahtinen, 38, is standing trial in St. Louis County District Court on charges of second-degree murder and first-degree manslaughter in the Sept. 4, 2008, death of the son of his former West Duluth neighbors.
Dr. David Posey, a forensic pathologist from La Canada, Calif., testified that he spent 125 hours reviewing police reports, microscopic slides, autopsy photographs and medical records before reaching his determination that Connor's death was accidental.
Public defender Scott Belfry had Posey explain to jurors the possible cause of the bruises that the infant had across his lower chest. "My opinion, based on everything that I've seen, these bruises are consistent with a fall from a port-a-crib," Posey testified. "... I see no pattern to indicate a foot or shoe."
Posey testified that he was confident the boy's injuries were not caused by a foot and were more consistent with a fall. He said, because of the forces generated, he would have expected greater injuries if the boy had been kicked.
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Assistant St. Louis County Medical Examiner Dr. Donald Kundel performed the autopsy on Connor. Kundel testified earlier in the trial that his opinion was that the child suffered a blow to his abdomen -- consistent with being stomped on -- that burst his liver, and caused him to die from massive blood loss.
Tahtinen told Duluth police that the boy twice fell out of his portable playpen and that he did nothing to harm him.
Posey testified that the liver laceration could have been caused by the CPR performed on Connor. Records indicated that the boy received 5,500 chest compressions, the witness said.
Posey, a retired Army colonel, testified that he has performed more than 4,000 autopsies, and has testified at least 150 times for the prosecution and the defense. A Google search of his name indicates that he receives calls for his opinion from Nancy Grace of CNN and he provides expert forensic consultation for Discovery Channel documentaries on Unsolved Mysteries.
Posey was prepared to testify about biomechanics - the study of the mechanics of a living body, especially of the forces exerted by muscles and gravity on the skeletal structure -- to explain the forces that caused the boy's death from an alleged 30-inch fall from the top of the playpen to a carpeted floor below.
Outside the presence of the jury, St. Louis County prosecutor Gary Bjorklund challenged Posey's credentials and experience in being able to use biomechanics to explain the boy's death, leading the doctor to respond at one point: "I really feel like I'm being harassed."
Bjorklund pointed out to Posey that he had used the wrong methodology to reach a conclusion about the G forces - a force acting on a body as a result of acceleration or gravity. Posey initially reported that the G force of the boy's fall was 867 times the force of gravity. The witness said that he was under the time constraints of the court to submit his report and he provided the information even though he knew it was wrong. He later corrected it.
Bjorklund argued to Judge Sally Tarnowski that there were "so many holes" in Posey's knowledge that his testimony would be confusing to jurors. Belfry argued that his witness has testified about biomechanics in other courts and is qualified to do so.
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Tarnowski ruled that Posey could provide testimony regarding blood clotting and his opinion of the speed the boy was traveling when he allegedly fell, 8.65 mph, but that the doctor didn't provide the foundation to prove to the court that he was qualified to testify about bio-mechanical G forces and kinetic injury and he could not present that type of testimony to jurors.
Also outside the presence of jurors, Tarnowski admonished Tahtinen for having an apparent emotional reaction to the autopsy photos. The judge told the defendant that he had been previously warned and that if he did it again he would be admonished in front of the jury.
