The Amir family, which has faced ten years of defamations and hatred from wide sectors of the Israeli public, remained firm in its belief that Yigal has been mistreated by the justice system.
The family has long since advocated an alternative version to the memory of the murder.
A petition posted on the family's website Thursday called for the release of both Yigal and his brother Hagai from jail.
According to the petition, "the security realities in Israel have proved that Yitzhak Rabin committed a crime against his people when he surrendered our lives and our safety to our most bitter enemy."
"An offense committed against a criminal calls for a much lighter punishment than an offense committed against an ordinary citizen," the petition continued.
"Therefore, ten years in prison, in disgraceful isolation conditions, should be considered a satisfactory punishment for breaking the country's laws," the petition stated.
Harsh responses in the political system
Minister Haim Ramon (Labor) blasted the Amir family initiative to petition for the liberation of the two brothers.
"It appears that the Amir family is not satisfied with the fact that its son has killed Rabin, and it wishes to murder his memory as well," Ramon said. "The entire family should lock itself up in prison and remain silent forever," he added furiously.
MK Ran Cohen (Meretz-Yachad) said he intends to file a complaint against the family following their declarations.
"The family, and those it represents are enemies of Israel, of the Jewish people and of democracy," Cohen stated.
"The real danger lies in the fact that this family dares to demand the release of this vile murderer, who triggered the greatest rift in Israeli society ever," he said.
The audacity of the Amir family knows no boundaries, Deputy Minister Orit Noked ((Labor) said in response. "Neither time nor their repulsive nonsense can erase this horrible crime from memory," she said.
General Secretary of the Peace Now movement Yaniv Oppenheimer said that the president must pledge Amir will never be granted a pardon.
Labor young guard members approached the attorney general Thursday and urged him to launch an investigation against the Amir family and the operators of its web site.
"The Amir family's incitements will provoke another political murder, and therefore the law enforcement authorities are obligated to act," Eran Hermoni, head of the young guard said.
'They lost all shame'
The spokesman of the Yitzhak Rabin Center, Moshe Debby said that "the delusional allegations made by the family are detached not only from reality, but from democracy as well."
"Yitzhak Rabin was an elected prime minister who operated on the mandate given to him by the Israeli public, and in Israel's interests. He was murdered in a political assassination, and his killer, Yigal Amir, should spend the rest of his life in prison" Debby concluded.
Internal Minister Ophir Paz Pines said in response to the statements that "ten years after the murder, the Amir family has lost what little shame it had left."
"This is a family who raised an appalling murderer, and instead of condemning him, it even dares to laud him," he added.
The current petition, Paz Pines stressed, proved the importance of the law that prohibits Amir's discharge.
Ronny Sofer contributed to this report