The former Iraqi president and seven co-defendants are charged in connection with the deaths of 148 Shia from Dujail after a failed assassination attempt on the former leader in 1982.
The first defence witness to appear on Monday spoke from behind a curtain and gave evidence in connection with defendant Ali Daieh.
He said he knew of two people who were not executed for the Dujail attack but whose names appear on the list.
The witness said: "One of them called Nabil, I know him. He was killed in the Iraq-Iran war in late 1982. I attended his funeral.
"The second, Abbas Habib Jafar, this guy was executed in 1981," he said.
The general prosecutor gave the court the list of 148 people allegedly executed.
Complainants and prosecution witnesses said there was no assassination attempt on July 8, 1982, and the bullets were celebration shots by people showing their happiness at seeing the president in their village.
Defendants and defence lawyers argue there was a pre-planned assassination attempt by the then banned al-Dawa party. The defence argues that the al-Dawa party issued statements claiming responsibility for the assassination bid.
Jafar al-Musawi, the general prosecutor, says hundreds of villagers were rounded up after the assassination attempt, many were tortured and 148 executed.