On Wednesday, jurors heard potentially damaging testimony for a former Mount Kisco police officer who's facing manslaughter charges in an immigrant's death.

Westchester County medical examiner Millard Hyland said Rene Perez died from blunt force trauma to his abdomen. Highland identified bruising in the shape of three knuckles during the autopsy, indicating that Perez was dealt a "catastrophic" blow.

During cross-examination, Hyland admitted that he had never seen such bruises, but maintained that Perez died from internal bleeding due to a beating. The defense argued the injuries may have been present before. Hyland disagreed, saying Perez would have been unable to put on a sweatshirt or even call 911, as he was seen doing on surveillance video.

The testimony marked the first time in the trial the jury heard graphic details of Perez's injuries. He was found near death on a Bedford road after calling 911 for help.

A toxicologist also testified Wednesday that Perez's blood-alcohol level was .29, three times the legal limit.Testimony resumes Friday, June 6. George Bubaris, who quit the force after the incident, is accused of beating up Perez and dumping him on the side of a road to die in April 2007.