The retrial has begun in Egypt of two Al Jazeera journalists convicted last year of spreading false news to help a terrorist group.
Mohamed Fahmy and Baher Mohamed were imprisoned along with their Australian colleague, Peter Greste.
An appeals court ordered a retrial last month, saying the original court's verdict was not supported by evidence.
Mr Greste was freed last week under a law allowing the deportation of foreign nationals to their home countries.
Mr Fahmy has since given up his Egyptian citizenship to qualify for deportation to Canada, but Mr Mohamed has no foreign passport.
The journalists strenuously deny collaborating with the banned Muslim Brotherhood after the overthrow of President Mohammed Morsi by the military in 2013. They say they were jailed simply for reporting the news.
'Worst nightmare'
The first trial of the journalists was widely condemned internationally, and the Court of Cassation ruled on 1 January the the Cairo Criminal Court had been "hasty in pronouncing its verdict".
On Monday, the deputy head of the Court of Cassation, Judge Anwar Gabry, said prosecutors had failed to present conclusive evidence that the defendants helped the Brotherhood or promoted the group.
- 29 December 2013: Peter Greste and Mohamed Fahmy arrested in police raid on Cairo's Marriott Hotel. Baher Mohamed later arrested at home
- 29 January 2014: 20 people including the three journalists referred to trial, charged with spreading false news, belonging to a terrorist organisation and operating without a permit
- 22 February: First court appearance of the three journalists
- 23 June: Defendants sentenced to seven years, with Baher Mohamed receiving an additional three years
- 12 November: President Sisi signs decree allowing repatriation of foreign prisoners
- 1 January 2015: Highest court orders retrial, but the three journalists not allowed bail
- 1 February 2015: Peter Greste freed and deported, his two colleagues remain behind bars
How journalists were jailed in Egypt
Who are the jailed journalists?
He also said the trial had failed to investigate claims that the defendants had given testimony under duress, and as a result "the Court of Cassation is unable to show how right or wrong the verdict is".
Families of the journalists worry the process may not be fairer the second time around, reports the BBC's Orla Guerin in Cairo.
Mr Fahmy's relatives have described the retrial as their worst nightmare.
Mr Mohamed's wife, Jihan, said the case should have ended with Peter Greste's deportation
Mr Greste, who arrived back in Australia last week, said his thoughts were with his colleagues
Canadian officials have called for his immediate release, saying there were assurances that he would be freed with Mr Greste.
"We had assurances from the Canadian government and Egyptian officials that Mohamed was supposed to be out last Tuesday," Mr Fahmy's fiancee, Marwa Omara, told the AFP news agency. "I quit my job and packed my bags."
Mr Mohamed's wife, Jihan, said the case should have ended with Mr Greste's departure, and she hoped her husband would be released soon. She said it was unjust for him to be on trial when a colleague convicted in the case was already a free man.
Mr Greste said his thoughts were with his colleagues.
"Strange feeling to watch my cell mates and brothers Fahmy & Baher in court from the outside. My heart is in the cage with them #FreeAJStaff," he wrote on Twitter.
Our correspondent says lawyers for the journalists are expected to press for the charges to be dismissed, or at a minimum for them to be granted bail.
President Abdul Fattah al-Sisi, the former military chief who ousted Mr Morsi, has said he will not consider a pardon before the courts have finished their work.
The initial trial took place amid strained relations between Egypt and Qatar, which owns Al Jazeera and supported Mr Morsi.
But in recent months, Qatar has expelled several senior Brotherhood leaders it was hosting and also suspended broadcasts by Al Jazeera's Egyptian affiliate, Mubasher Misr.
