The question of the Shiites' prosecution is a key point in the trial of Saddam Hussein and seven former members of his regime.
The eight are charged with killing the Shiites, as well as illegal imprisonment and torture of hundreds of others - including women and children - in a crackdown launched against the town of Dujail following a 1982 assassination attempt against Saddam.
Saddam has admitted that he ordered the trial of the 148 before his Revolutionary Court. But he said he had the right to do so because they were accused in the attempt to kill him.
Prosecutors have said the trial was "imaginary," that the 148 did not even appear before the Revolutionary Court that sentenced them to death.
"The trial is beginning to take shape since the recess, with Saddam Hussein testifying instead of boycotting the court," said CBS News Foreign Affairs Analyst Pamela Falk, "and a formal charging document is anticipated after this stage of the trial, meaning that the trial is actually proceeding faster than some analysts had expected."
Testifying in court Monday, Saddam's co-defendant Awad al-Bandar - who headed the Revolutionary Court at the time - said he sentenced the 148 to death but insisted their trial was conducted "in accordance with the law."
"The court had no choice but to implement the law," he said.
The chief judge in the Saddam trial, Raouf Abdel-Rahman grilled al-Bandar over the 1984 trial, asking how all 148 defendants could have fit in the court, and how the two-week trial could have been conducted so quickly.
"How did you take the testimonies of 148 persons that quickly?" the judge asked him. Al-Bandar said the 148 had confessed. "We were at war with Iran, and they confessed that they did their act at orders coming from Iran," he said.
Saddam and his co-defendants have depicted the crackdown as a legal response to the assassination attempt on July 8, 1982, when gunmen opened fire on Saddam's motorcade as he drove through Dujail, north of Baghdad.
But prosecutors have sought to show Saddam's regime sought to punish the town's civilian population. Hundreds of people were arrested - including entire families, with women and young children - and detained for years. They have produced documents showing 10 juveniles were among those sentenced to death.
"Are you saying all 148 participated in the shooting?" Abdel-Rahman asked al-Bandar, who repeated that they had confessed. "The confessions were confirmed," al-Bandar insisted.
Al-Bandar said all those who were tried were above the age of 18. Pressed by the chief prosecutor about the ages, al-Bandar said, "This was quarter of a century ago. Do you expect me to remember? There were the old and there were the young, but all of them were adults."
Al-Bandar's comments came as the court for a second straight session heard direct testimony from the defendants for the first time. Each of the eight defendants is to appear, one by one, to be questioned by Abdel-Rahman and the chief prosecutor.
On Sunday, three defendants - local members of Saddam's former ruling Baath Party - testified, denying accusations they informed the security forces and the feared Mukhabarat intelligence agency about Dujail families who were subsequently arrested.
It is not known when Saddam is next due to appear, since it is up to the chief judge to decide the order. If he goes last, his turn is likely to come in a later session.
Also still to be heard are the other top defendants in the case, including Saddam's half-brother and former intelligence chief Barzan Ibrahim and Saddam's former vice president, Taha Yassin Ramadan.
After the defendants testify, the defense can produce witnesses or documentation it wishes.
Under the Iraqi justice system, that will end the first portion of the trial. The five-judge panel will call a recess and draw up exact charges against the defendants. The court will then reconvene and the prosecution and defense will each have their turn to address the charges.