Mystic - Charles Buck may be facing trial for allegedly killing his wife, Leslie, in May of 2002, but the medical examiner who performed her autopsy said Monday she does not know if Leslie was even the victim of a homicide.

During a hearing in New London Superior Court, Buck's attorney, Hubert Santos, questioned retired associate state medical examiner Dr. Malka Shah about her autopsy report, in which she stated that while Leslie died of a head injury, she did not have enough information to say how she suffered it.

"As we sit here today, you cannot say with a reasonable degree of medical certainty that this case was a homicide?" Santos asked Shah.

"I don't know," she answered.

A few moments later, senior assistant state's attorney Paul Narducci asked Shah if she could say that it was not a homicide. Shah said she could not say that either, adding it was unusual not to be able to determine a manner of death.

The exchange came during the third day of testimony in the hearing in which Judge Susan B. Handy will determine if there is probable cause for the case to proceed to trial. Shah's uncertainty could be used by Santos to convince Handy the case should not go to trial or be used to convince jurors that there is reasonable doubt that Buck killed his wife.

During the almost three and a half hours of testimony from Shah, Santos and Narducci asked numerous questions about the laceration Leslie Buck suffered to her forehead and the skull fracture she sustained to the back of her head. It's that injury that Shah said killed the second-grade teacher at Deans Mill School in Stonington. Santos also asked questions about the condition of her heart, which showed signs of abnormal inflammation.

Charles Buck, dressed in an orange prison jumpsuit and shackled at his ankles, showed no emotion when Narducci used a projector to show a photo of Leslie's face taken at the autopsy. The laceration could clearly be seen on her forehead. During recesses when he had to leave the courtroom, Buck gazed around the gallery and at one point stared at his wife's friends.

When Narducci showed the autopsy photos, including one of Leslie Buck's skull, her friends and former colleagues looked away. One buried her head in her hands. When Narducci finished, Handy asked him to take the photos down. The judge has sealed the photos, which she called "quite gruesome," from the public.

Under questioning by Narducci, Shah said the fracture to the back of the skull probably occurred when Leslie Buck, 57, fell down the stairs in the couple's Mystic home in May of 2002. But Shah, who visited the home, said she could not find anything in the area of the stairwell that would have caused the 3-centimeter laceration to Mrs. Buck's forehead. Shah said that injury was caused by a blunt object that cut the victim's skin and struck her from above.

Police have alleged that Charles Buck used a piece of wire club to strike his wife in the head. Police never found that club. Shah said Buck died almost immediately after sustaining both injuries.

During Santos' questioning, Shah reiterated that it is possible to die from a skull injury that does not cause a brain injury, which is what she said happened to Leslie Buck. She said the skull fracture was the most significant injury she found while examining her body.

The hearing will resume Monday.

j.wojtas@theday.com