Egypt's fallen President, his sons and security chiefs will learn on Saturday whether they have been found guilty of murder and corruption after a trial in a region where autocrats once ruled with impunity.

Hosni Mubarak's trial, which began last August six months after his ouster in a nationwide uprising, has critics fearing that they may see justice foiled yet again because of the lack of hard evidence against the former dictator.

The verdict comes at a time of deep polarisation in a country under a tumultuous military-led transition.

Since Mubarak's incarceration in April 2011, huge changes have swept the country, culminating in a first-round election for a new President earlier that narrowed the field to a contest between a Muslim Brotherhood candidate and Mubarak's last premier.

Islamists who had before been banned or jailed are now at the forefront of politics after a big win in parliamentary elections, and the nation has become divided by the uprising and its sometimes deadly aftermath.

Mubarak is charged with corruption and the killing of demonstrators during the uprising that toppled him in February 2011. He shares the murder charges with seven security chiefs and the corruption charges with his two sons, Alaa and Gamal.

Roughly 850 protesters were killed during the 18-day uprising that forced Mubarak to resign.

Despite decades of human rights violations, political detentions and a deadly institution of torture under Mubarak's watch, the ex-strongman may yet win an acquittal, or an appeal should he be found guilty.

Over the course of 36 hearings, families of Mubarak's alleged victims watched the proceedings with sinking hearts as the prosecution's witnesses contradicted themselves or even appeared to exonerate Mubarak and his security chiefs of the murder charges.

The prosecution has called for the death sentence against Mubarak, and argued in its closing arguments that it had compiled enough evidence for a conviction.

But its witnesses painted a different picture.

One, a police officer, said he had been ordered to treat protesters as brothers. And several said they were ordered not to carry deadly weapons during the protests.

Yet another prosecution witness, who had been a deputy to former interior minister Habib al-Adly, Mubarak's co-defendant, said Adly had issued orders to use only tear gas and water cannon on January 28, 2011, the deadliest day of uprising.

"The prosecution's witnesses are actually defence witnesses," muttered one lawyer representing families of the victims.

Several heavyweights, such as the country's military ruler Field Marshal Hussein Tantawi, testified behind closed doors, but lawyers for the victims who attended the session said they did not implicate Mubarak.

Aside from the murder charge, Mubarak also faces corruption charges in relation to sales of gas to Israel at below market prices and for accepting a bribe from co-defendant Hussein Salem, a businessman.

The military that took charge after Mubarak's ouster has always denied that it had a role in placing him on trial, insisting that the judiciary is independent.

But the trial came after months of anti-military protests calling for the dictator's trial.

The verdict comes as Egyptians prepare to vote for a new president on June 16 and 17 in a run-off after last week's elections failed to yield an outright winner from among 12 candidates.

Ahmed Shafiq, the last prime minister to serve under Mubarak will face the powerful Muslim Brotherhood's candidate Mohammed Mursi.

A Shafiq victory may leave Mubarak, who is detained in a military hospital, feeling vindicated. The 84-year-old strongman had always argued that Islamists and tumult would grip the country if he stepped down.