He said it was "telltale" that the court sentenced Amanda to 26 years instead of life in prison like the prosecution demanded.
"I'm not sure they really believe in what they came about," he said.
He noted that Sen. Maria Cantwell, D-Wash., condemned the sentence today and had spoken to the Italian embassy and to Secretary of State Hillary Clinton about the verdict.
When asked if he expected the State Department to get involved in his daughter's case, Curt Knox said, "I would be very disappointed if they didn't, very disappointed."
Deanna Knox was defiant.
"We're not accepting it," she said. "We will bring her home."
The Knox family already has spent more than $1 million in hiring a legal team and keeping a family member in Italy at all times to visit Amanda.
When asked how he will pay for an appeal and to keep someone in Italy, Curt Knox said, "We'll figure it out. She will not be left here."