Dr Cyril Wecht, who investigated high profile deaths like the Kennedy assassination and Anna Nicole Smith's drug overdose told the Dr Phil show that he "strongly doubted" she killed herself.
As we reported here Zahau, 32, was found hanging, arms and legs bound from the balcony of her multi-millionaire boyfriend Jonah Shacknai's, 27 bedroom Coronado, CA home, known locally as Spreckles mansion.
Cops ruled her death a suicide, something her family have always disputed and Dr Wecht seems to agree after performing a second independent autopsy on her body.
While he agreed with the official verdict that she died from asphyxiation he said that he strongly doubted she killed herself.
He said: "I lean very strongly toward it being a homicide, something involving foul play. And I lean very strongly against it being a suicide."
He added that he was particularly troubled by findings in both autopsies that Miss Zahau had suffered blows to the top of her head, indicated by four separate haemorrhages beneath the scalp.
Such an injury, he explained pointed to the possibility that she was knocked unconscious with a blunt object and could explain why police said there was no sign of a struggle at the scene.
He was also confused about why Miss Zahau's neck was not broken by the force of her fall from the balcony while he claimed the way she had tied herself up was possible, but implausible