The parents of murdered US journalist Daniel Pearl have filed an appeal with Pakistan's Supreme Court to reverse a ruling overturning the convictions of four men in the case.
Pearl was kidnapped and beheaded in 2002 while investigating Islamist militants in Karachi, Pakistan.
Last month a court in Karachi overturned the death sentence of the man convicted of masterminding the killing, and acquitted three others.
The ruling was widely condemned.
Pearl was the Wall Street Journal's Asia bureau chief when he was abducted and killed. A graphic video of his killing was sent to the US consulate a month later.
In a video statement, his father Judea Pearl said: "We have filed an appeal of this decision to the Pakistan Supreme Court.
"We are standing up for justice not only for our son, but for all our dear friends in Pakistan so they can live in a society free of violence and terror and raise their children in peace and harmony."
Their petition adds to one already filed by prosecutors.
The accused mastermind of the 9/11 attacks, Khalid Sheikh Mohammed, who is being held at Guantanamo Bay detention centre, has said he personally beheaded Pearl.
Mohammed told US interrogators he killed the journalist with his "blessed right hand", according to the Pentagon. The confession was made under torture and Mohammed - whose trial date for the 11 September 2001 attacks has been set for next year - has not been charged with Pearl's murder.
Shortly after their acquittal the four men - including the convicted mastermind Ahmed Omar Saeed Sheikh - were re-arrested. They will be held for at least three months as the appeals play out.
Sheikh's death sentence had been reduced to seven years in prison for kidnapping.
The Committee to Protect Journalists voiced its support for the appeal, and said that releasing the four men in the case "would only add to the threats facing journalists in Pakistan and deepen Pakistan's reputation as a haven for terrorists".
What happened to Daniel Pearl?
Pearl went missing in January 2002.
He had been researching links between Islamist militant activity in Karachi and Richard Reid, who tried to blow up a passenger plane using bombs hidden in his shoes.
According to prosecutors, Sheikh lured him to a meeting with an Islamic cleric. The two had built up a relationship discussing concerns about their wives, who were both pregnant at the time.
Almost a month later, a video showing the 38-year-old's beheading was sent to the US consulate in Karachi.
Pearl's son, Adam, was born in May 2002.
Sheikh was convicted of Pearl's murder in July 2002 by an anti-terrorism court, and has been on death row since.
Who is Ahmed Omar Saeed Sheikh?
Sheikh was born in London in 1973, where he attended public school before going on to study at the London School of Economics. He did not graduate, failing to return after driving aid to conflict-wracked Bosnia after his first year.
He was arrested for involvement in the kidnapping of four tourists - three British and one American - in Delhi in 1994.
Sheikh was released from prison as part of demands by militants who hijacked a plane in 1999.
According to news agency Reuters, police in India later accused him of transferring money to one of the militants who flew a plane into the World Trade Center on 9/11.