Spreckels Mansion Hanging Wasn't a Suicide, Victim's Sister Tells ABC News

July 19, 2011— -- The sister of a woman allegedly found hanged at a millionaire's historic mansion has rejected suggestions that she could have committed suicide.

The body of Rebecca Zahau, 32, was found on the grounds of the Spreckels Mansion in Coronado, Calif., last Wednesday. Her hands and feet were bound.

Two days before Zahau's body was found, 6-year-old Max Shacknai fell down the stairs at the mansion, which is owned by his father, pharmaceutical mogul Jonah Schaknai. The boy died of his injuries on Sunday.

Autopsies are being conducted on both bodies and the San Diego sheriff's office said today it's unclear if the boy's injuries are related to Zahau's death.

"Our investigation would include Max's incident," San Diego sheriff spokesman Roy Frank told ABCNews.com. "As far as if they are related, that's something we are just going to have to wait and see."

Police also said they are trying to determine whether Zahau, who had been dating Jonah Shacknai for three years, committed suicide or was the victim of a homicide.

Spreckels Mansion Mystery Deaths

"Rebecca was a beautiful, vibrant, loving and kind person and she would never do this to herself," Zahau's sister Mary Zahau-Loehner told ABC News.

The sisters spoke the night before Zahau died, she said, and Rebecca talked about her plans for the following day.

"She was going to call mom and dad the next morning and text me throughout the day with updates on Max," said Zahau-Loehner. "She was very hopeful. She had to be strong and there for Jonah."

Zahau and Shacknai seemed happy together, her sister said.

Authorities discovered Zahau's body at the mansion last Wednesday after Shacknai's brother Adam Shacknai told police he found her naked with a rope around her neck, hanging from a balcony off the main house.

When police arrived they found Zahau on the back lawn, her hands tied behind her back and her feet bound. Adam Shacknai told police he had cut her down.

The fact that Zahau's hands were tied behind her back does not rule out suicide, police said.

"We have had other cases in the past where people have used creative ways to commit suicide" including people whose hands were tied behind their back, Frank told ABCNews.com.

Police said Max's autopsy is "routine for anyone who dies who isn't under the care of a doctor when the accident occurs," Coronado police spokesperson Lea Corbin told ABCNews.com today.

Although Max died in a hospital under a doctor's care, Corbin said, "He was being cared for by a doctor, but we don't know why he died physically."

When Max fell on July 11, police received a call from a woman at the mansion who they would not identify, requesting medical aid for Max. Another person, a young female, was also present at the time of the accident, police said.

Max "had fallen from stairs and was not breathing and did not have a pulse," Coronado Police Chief Louis Scanlon told reporters last week. Paramedics performed CPR and the boy was hospitalized. He died Sunday.

Jonah Shacknai sent out a statement asking for privacy as he and his ex-wife Dina, Max's mother, grieve for their son affectionately known as Maxie.

"Despite heroic efforts on the part of paramedics and hospital staff, he was unable to recover from the injuries suffered early last week. His loving, kind and vibrant spirit will forever be in our hearts and those whom he touched every day. The loss to our families, Max's many friends of all ages and teammates, and the community is immeasurable," he wrote.