Renowned forensic pathologist Dr. Cyril Wecht expressed "grave and serious doubts" that the woman found bound, naked and hanging at her boyfriend's Coronado, Calif., mansion killed herself.
Rebecca Zahau, whose death has been ruled a suicide, died in July just two days after her boyfriend's son was fatally injured while under her care. Zahau's family believes she was murdered, and exhumed her body so Wecht could conduct a second autopsy.
Today he shared the results on the "Dr. Phil" show, which helped fund the exhumation.
"The autopsy itself was thorough, I have no criticism," Wecht said. "It's the findings that were there and some that were not there that … leave me to express grave and serious doubts that the manner of death was suicide."
Wecht, who has conducted more than 17,000 autopsies, suggested Zahau may have been hit on the head before she died of hanging. He told McGraw that four hemorrhages beneath Zahau's scalp aren't explained by a vertical hanging.
"You have to have blunt force trauma," he said after the show aired blurred footage from the autopsy.
"You have something of a rounded, smooth surface that impacts against the scalp, thus not producing a laceration," Wecht said.
Wecht said Zahau may have been knocked unconscious, which could explain why there are not defensive injuries on her body consistent with that of a struggle.
He agreed with the original autopsy report's conclusion that Zahau's cause of death was hanging, but he suggested she might have been placed in the noose.
Wecht also questioned the investigators' conclusion that Zahau had thrown herself over the balcony.
"We have no fracture of the cervical vertebrae [neck]," said Wecht. "That bothers me greatly with this kind of situation."
He suggested changing the manner of death from "suicide" to "undetermined" on Zahau's death certificate.
Dr. Phil devoted two episodes this week to the mysterious and complicated case that has generated national news headlines ever since the summer.
In July Zahau and her boyfriend of three years, Jonah Shacknai, were staying at his historic home in Coronado, Calif., when Shacknai's 6-year-old son Max seriously injured himself after tumbling off a balcony at the top of a stairwell at the mansion. The boy went into a coma and died several days later.
Zahau's death occurred two days after Max fell and just hours after police say Zahau received a devastating phone call from Shacknai about Max's grave condition.
Shacknai's brother, who was staying at the mansion as a houseguest, called 911 after he discovered Zahau hanging from the balcony. When police arrived they found Zahau's naked body on the lawn. Her mouth was gagged with a T-shirt and her hands were tied behind her back with red rope, secured by a slip knot. Her feet were also bound.
Police found a cryptic message written in black paint inside, on the bedroom wall. "She saved him. Can you save her," it read.
Investigators ruled Zahau's death a suicide, and Max's death an accident, but Zahau's family has never accepted the conclusion that Zahau would have killed herself.
Zahau's sister, Mary Zahau-Loehner, told McGraw that police "did not give my sister a fair investigation."
"My sister did not indicate that she was depressed, suicidal, or that she wanted to hurt herself," Zahau-Loehner said. "It still feels like a dream or some bad horror movie."
Dr. Lawrence Kobilinsky, a DNA expert and forensic scientist who heads the Department of Sciences at the City University of New York's John Jay College of Criminal Justice, shared similar suspicions with ABCNews.com in September, saying the injuries as described in the autopsy report suggested "a substantial blow to the head."
"There are four hemorrhages in four different positions," Kobilinsky said at the time. "When you see these kinds of scalp hemorrhages you have to explain them."
San Diego medical examiner Dr. Jonathan Lucas issued a statement in response to September press inquiries about the autopsy report. With regard to the hemorrhages, he said, "Because there was evidence that she went over the balcony in a non-vertical position, she may have struck her head on the balcony on the way down."
The sheriff's department admonished Wecht and the family's lawyer Anne Bremner, for taking the autopsy results to the "Dr. Phil" show before showing them to authorities.
In a statement released Monday, the San Diego Sheriff's Department said: "To date, neither our detectives nor the Medical Examiner's Office have been presented with any evidence from this second autopsy. If Dr. Wecht or Miss Bremner would like to share information they believe is pertinent with our investigators, we would be glad to meet with them, rather than hear their results on television provided as entertainment."
Although the "Dr. Phil" show presented no new evidence, Bremner raised additional concerns about the police investigation, questioning why a woman's pair of underwear found in the mansion's guest home had never been analyzed, and why two neighbors reported having heard a woman screaming.
The family claims the San Diego investigators assumed Zahau received difficult news about Max in the hours before her death, but because that voicemail message had been deleted from Zahau's phone they say it's impossible to know what it really said.
"Nobody has heard what the voicemail says," said Zahau-Loehner. "It's gone and wasn't retrieved from AT&T when it could have been done."
The family also disputes the message written on the bedroom wall in black paint. Although Zahau liked to paint as a hobby, they say the handwriting doesn't look like hers -- and the message did sound like her either.
"My sister writes everything every elaborately," said Zahau-Loehner. "If she's going to leave a message, that's not going to be the message."
McGraw pointed out Zahau could have felt "terribly guilty" about Max's injury and as a result decided to end her life.
But Zahau-Loehner told McGraw her sister "didn't feel guilty about it," citing a text message Zahau sent that said, in part, "I need to be strong for Jonah."
McGraw noted "naked suicide" is "almost always involved with severe guilt in some way" as opposed to other devastating events.
Zahau-Loehner and her husband Doug Loehner, who also appeared on the show, remained adamant that Rebecca Zahau wouldn't have killed herself, telling McGraw the family wants the California Attorney General to appoint an independent investigation.
"She would want us to find out the truth of what happened to her," Zahau-Loehner said. "She would do the same for me if it was the other way around."