BANGOR – The state medical examiner told a Penobscot County jury Monday afternoon that Michael Demmons most likely would not have survived the severe beating he received on a summer night in 2006, even if plastic bags had not been tied over his head and he had received immediate medical attention.

The murder trial of Peter Tuller, 35, of Bangor began Monday in Penobscot County Superior Court. He allegedly beat, hog-tied and secured white trash bags and a pillowcase over Demmons’ head on June 25, 2006.

State Medical Examiner Dr. Margaret Greenwald testified that Demmons died of a combination of blunt-force trauma to the head, neck and chest and of suffocation. She said that the victim had between 10 and 12 skull fractures along with bruises, cuts and abrasions on his face and neck.

Greenwald said that during an autopsy she found that nine of the 12 ribs on the left side of Demmons’ body and six on his right were broken. All of the ribs had between two and four fractures each, she told the jury.

The severe damage to Demmons’ left side caused him to suffer from “flailed chest,” the medical examiner testified. Greenwald said that meant the muscles separated from the ribcage so that the left side of his chest could not expand when Demmons’ took a breath, causing his left lung to collapse.

Under cross-examination, the medical examiner said the victim’s blood-alcohol level was 0.31 percent, or nearly three times the legal limit of 0.08 percent.

Demmons was staying with his friend Maria Santos, 46, of Bangor when he was killed in her Pier Street apartment. Tuller, who police found hiding in the apartment when they discovered the victim’s beaten and bloodied body, was described in court documents as Santos’ former boyfriend.

Santos is expected to be called late today or Wednesday as a witness for the defense, not the prosecution. She told Superior Court Justice Joseph Jabar on Monday while the jury was not in the courtroom that if asked about her possible role in Demmons’ death, she would exert her Fifth Amendment right to not incriminate herself.

She has not been charged in connection with Demmons’ death.

Bangor police officers testified Monday that they were sent to a service station on Hammond Street and West Broadway about 9 p.m. June 25, 2006, after a caller reported that a woman was talking on her cell phone about a dead body.

Officer Chad Foley testified that he and other officers found a crying and intoxicated Santos at the gas station. Foley recognized the woman as Maria Santos because he had dealt with her in previous incidents, he said.

He and other officers went to Santos’ nearby apartment on Pier Street, Foley said. Once inside, they found Demmons’ body in one bedroom. In another bedroom, they found Tuller hiding under the bed. He surrendered without incident.

Bangor police Detective Lawrence Ellis testified about how he photographed the scene and collected evidence, including bloodstained clothing from the defendant. He identified photos taken of the crime scene for the jury along with the extension cord recovered from the victim’s body and the blood-soaked plastic bags placed over his head.

Under cross-examination, Ellis said that he was unable to recover any fingerprints from the trash bags.

Tuller allegedly admitted to police that he punched Demmons and tied him up, but he claimed that Santos placed the plastic bags over the victim’s head. Santos told the Bangor Daily News a few days after Demmons’ murder that she had nothing to do with his death. She allegedly told police in June 2006 during interviews about the homicide that she had tried to stop the attack, but was slammed up against a wall by a knife-wielding Tuller.

Demmons’ five siblings and other family members filled the courtroom Monday.

“We’re glad there’s going to be closure,” the victim’s sister, Laurie Stevenson, 42, of Brunswick said during a break. She also said that their 77-year-old father, Walter Demmons, recently suffered a heart attack and was hospitalized. Their mother is deceased, she said.

Stevenson said that Michael Demmons, who has cerebral palsy, had the IQ of a 14-year-old and would not have known how to defend himself if attacked. She said he had lived with her in 2005 and 2006.

“Part of me feels like this is just a bad dream,” she said of listening to testimony and seeing crime scene photos Monday. “It’s like I’m watching a TV show like ‘Law and Order’ or ‘CSI.’ It’s pretty intense.”

Stevenson, who wept as she talked, also said she was not aware how severely her brother had been beaten until Assistant Attorney General Andrew Benson, who is prosecuting the case, described his injuries in his opening statement.

“I guess, in my mind, I was just thinking about the hog-tying versus the beating he went through,” she said. “I thought that he suffocated and hoped it was over quickly but he really suffered. He was tortured.”

The trial is expected to continue today with testimony from Maine Crime Lab technicians.

Closing arguments before the jury of nine women and five men, including two alternates, are expected to begin Wednesday afternoon.

If convicted, Tuller faces between 25 years and life in prison.