Rebecca Zahau Death: Disturbing Reenactment Tries to Determine Whether She Could Have Killed Herself

The "20/20" investigation also looked into the complex knots used to bind her hands.

ABC's 20/20 has investigated the strange death of 32-year-old Rebecca Zahau, including recreating her demise by hanging in what authorities have declared a suicide.

The girlfriend of millionaire Jonah Shacknai was found hanging in the foyer of his California mansion, with her hands and feet bound. Shacknai's brother, Adam, discovered the body and called 911.

911 Operator: "911 Emergency. What are you reporting?"

Caller: "I got a girl hung herself."

911 Operator: "Is she still alive?"

Caller: "I don't think so."

For 20/20, former NYPD Det. Herman Weisberg asked a boat captain and knot expert to tie his hands the way Rebecca's were bound. 

He had some difficulty binding his hands behind his own back, but was ultimately able to do it.

But the news program found some issues with the suicide, most notably that Rebecca, while bound and naked, was able to hop over the balcony railing and fall to her death.

Her family is suing Adam Shacknai for wrongful death, claiming she would never commit suicide, and that he is responsible for what happened. He denies the allegations.

In recreating her fall, 20/20's expert suggests it's possible that someone threw Rebecca over the balcony.

Jonah Shacknai believes Rebecca killed herself over the accidental death of his 6-year-old son, who fell down the stairs just days prior, while in Rebecca's care.

"It's hard to sit here and rationally examine what might have gone through someone's head at the moment they lost reason and did something horrible to themselves," he said.