Coronado home of CEO Jonah Shacknai
The Coronado home of Medicis Pharmaceutical Corp chief executive Jonah Shacknai is pictured in California July 14, 2011. Shacknai's girlfriend Rebecca Nalepa, 32, was discovered dead at his mansion prompting an investigation by homicide detectives, police said on Thursday. REUTERS

The mystery surrounding the twin deaths at businessman Jonah Shacknai's mansion in Coronado, Calif., deepened as it emerged that doctors thought the fall injuries suffered by Max Shacknai were inconsistent with the cause of his death.

Max Shacknai had fallen from a staircase at the Spreckels mansion in Coronado. Rebecca Zahau, his father's girl friend, found him unconscious and called the paramedics. When the medical team found him, he was not breathing and his neck was broken. He died a week later.

Two days after the boy's fall, 32-year-old Zahau, under whose care the boy had been, was found dead in a bizarre fashion at the mansion. Shacknai's brother, who was staying at the mansion, found her hanging from a second-storey balcony. She was nude and her hands and feet were bound with electric wires.

According to the latest reports, the boy's physician had said that the visible injuries did not likely cause his death. Earlier, Max's death had been judged as an accident by the San Diego Medical examiner.

However, the Daily Mail reported that the physician, Dr. Brad Peterson of Rady's Children's Hospital, told police that Max's visible injuries were not consistent with the cardiac arrest and brain swelling he suffered.

He did not feel the visible injuries were consistent with the cardiac arrest and brain swelling experienced by Shacknai, Peterson was quoted by the Coronado Police Department as saying in search warrants released by a San Diego judge.

According to police, Zahau was the only adult present at the house when Max fell. Zahau's teenage sister Xena was at the house too.

Investigators said early this month that the death of Zahau was a suicide, but the dead woman's sister has said the family was not convinced. It doesn't add up ... Nothing adds up, said her sister Mary Zahau-Loehner.

According to Zahau-Loehner, investigators did not find a suicide note. But they showed her text messages on Zahau's phone from months earlier about issues she had with Shacknai's children, according to the Daily Mail.

More importantly, Zahau-Loehner says she had spoken with her sister the night before she died and that she got no hint of anything going wrong with her.

Meanwhile, the California attorney general had declined Jonah Shacknai's request to investigate the mysterious deaths at the mansion, the Daily Mail report said. The attorney general's office informed the millionaire pharmaceutical giant that the California Department of Justice would conduct such an investigation only 'under very narrow circumstances.'