The San Diego County Sheriff's Department announced on Friday it had determined the cause of both the mysterious deaths that took place in Jonah Shacknai's Spreckels Mansion in July. Sheriff Bill Gore said the investigation -- a partnership between his department and the Coronado Police Department -- concluded that Max Shacknai's death was an accident and Rebecca Zahau's death was a suicide.

Jonah Shacknai's six year-old son, Max, was rushed to the hospital on Monday, July 11, after an accident on a staircase in his father's Coronado mansion. He was initially revived but died nearly a week later from the injuries.

Shackai's girlfriend, 32 year-old Rebecca Zahau, was found hanging at the mansion in the early hours of July 13 by Jonah's brother Adam Shacknai, who was staying in a guest house at the home. Jonah Shacknai was not present at the time.

Adam Shacknai told investigators he cut Nalepa down from the rope suspending her over a courtyard. She was naked, and both her ankles and wrists were bound, causing many to question how she might have taken her own life.

This is a very bizarre death, there's no doubt about it, San Diego Sheriff's Capt. Tim Curran told reporters shortly after the body was discovered.

In support of the suicide ruling, the San Diego Sheriff's department released a video demonstration of a woman tying her own wrists together behind her back, as Zahau's were:

Rope Demonstration - Front View from San Diego County Sheriff on Vimeo.

The Sheriff's department also released photos taken inside the house and a series of diagrams illustrating how Max Shacknai fell over a second-story banister and grabbed hold of a chandelier to break his fall. (The photos and transcripts of press statments can be found on the San Diego County Sheriff Department's Web site.)The investigation determined that Max was alone at the time, and must have been running in order to achieve the velocity that caused his fatal injuries.

One of the photos shows a door where Zahau purportedly painted a final message, although the message was blocked out in the image and the department declined to reveal its contents.

Zahau's ex-husband Neil Nalepa reportedly witnessed the message firsthand and told Coronado Patch it said: She saved him, can he save her.

While investigators pointed to the message -- which was written in English, Zahau's second language -- as a critical piece of evidence in the suicide ruling, Nalepa is not convinced.

It's mysterious, Nalepa said. It's not what Rebecca sounds like or talks like.

Rebecca Zahau's sister Mary Zahau-Loehner has insisted from the start the Rebecca was in a healthy state of mind before her death, and said nothing was out of the ordinary when the two spoke on the phone the evening of July 12, the night before her body was found.

She was normal, fine, just getting ready to go to bed, Zahau-Loehner told ABC News.

According to a timeline released by the Sheriff's Department, Zahau received a phone message at 12:50 a.m. which revealed that Max Shacknai's condition had worsened. She then gathered the materials to paint the message and hang herself, and died at approximately 3 a.m. of asphyxiation.

Authorities did not find any other fingerprints on the materials besides Rebecca's, but the Zahau family's lawyer, Anne Bremner, objected to this segment of the investigation, arguing that Jonah Shacknai's fingerprints were not collected and should have been. Bremner added that a perpetrator could have worn gloves to evade fingerprint detection.

She also said that Zahau's family is sure Rebecca would not have committed suicide based on her religious beliefs.

Coronado Patch reports that Zahau's family wants to the investigation to continue, and had asked the Sheriff's Department to consult with a forensic psychiatrist.

Once you say it's a closed investigation, you can open it again, Bremner told Coronado Patch.

Sheriff Gore said that the department had no plans to consult with a forensic psychiatrist, and is treating the case as closed.

We were pretty positive they were looking at the possibility of a homicide, Zahau's ex-husband Nalepa told Coronado Patch. It doesn't look like they ever did.