A forensic pathologist raised questions about what caused the marks on Neil Stonechild's face, as she testified at a hearing into the firing of Constables Larry Hartwig and Brad Senger on Tuesday.

The two were dismissed after an inquiry found they had contact with Stonechild on the last night he was seen alive.

Stonechild was the aboriginal teen whose frozen body was found in Saskatoon's north end in 1990.

Dr. Emma Lew, a medical examiner for the Miami Dade County in Florida, said the marks on Neil Stonechild's face were superficial scratches, which she believes happened shortly before his death. She said they were likely caused by frozen vegetation that he fell into.

Lew says handcuffs did not make the abrasions or scratches, as they are too smooth, and too thick to produce the kind of delicate scratches seen in the autopsy photos.

Lew also rejected the suggestion that handcuffs could have caused the marks on Stonechild's right wrist, saying instead that the mark looks more like a post-mortem injury she sees on dead bodies regularly. She believes it was caused by clothing, most likely the cuff of a sleeve.

Hugh Harradence, the lawyer for the Saskatoon Police Service, challenged Lew's testimony, saying she is not an expert on handcuff injuries, having studied only five cases involving the hand restraints.

Aaron Fox, the lawyer for Larry Hartwig disagreed, saying he would be surprised to find anybody with more expertise than she has.

Fox said that as a forensic pathologist, Lew has daily experience determining what causes certain marks on a body.

Lew has spent 14 years as a medical examiner, and during that time she has conducted over 3,000 autopsies.