Jurors in the first-degree murder trial of Jonathan Trask heard testimony Thursday from Dr. Chai S. Choi, a forensic pathologist with the Oklahoma Chief Medical Examiner, who performed an autopsy on 6-month-old Mackenzie Trask following the girl's death.

Assistant District Attorney Susan Caswell asked Choi if Trask's injuries were "consistent with falling off a bed," the story allegedly told to police by the parents.

"No," Choi replied. "She died from blunt force brain trauma, a cracked skull and fatal brain injuries."

Choi said the injuries, including a subdermal hemorrhage on the left side of her brain likely were caused by a "shaken impact injury by blunt force -- a common injury from child abuse."

Caswell asked what type of force was used to cause Mackenzie's death. "Was it violent force?" she asked.

Choi replied: "Yes. It's not mild force," adding she suspected the girl's death was caused by child abuse.

Mackenzie Trask died April 6, 2007. Jonathan Trask, 26, is charged with his wife Heather Trask, 24, with first-degree murder (child abuse) by the infliction of unreasonable force that allegedly resulted in the death of Mackenzie, or in the alternative, murder in the first degree by permitting the use of unreasonable force that resulted in the death of the girl.

Heather Trask is scheduled on the January felony call docket. The court decided to try the Trasks separately when it appeared the defenses of the codefendants were mutually antagonistic.

Wednesday, one of the first emergency responders to arrive at the family's Norman residence, said Mackenzie was "listless and blue and not breathing," and had no heart rate.

Testimony and slides shown to the jury indicated bruising was evident on the side of the girl's face, along with other external injuries including marks on her abdomen, abrasions on her buttocks, scratches on her arm and contusions on her fingers, Choi said.

The trial continues today in the courtroom of District Judge Tom Lucas. Oklahoma City attorney Gary James is representing Jonathan Trask.

Tom Blakey 366-3540 tblakey@normantranscript.com