Saddam Hussein was forced to attend his trial Monday, looking haggard and wearing a robe rather than his usual crisp suit as he shouted "Down with Bush." His top co-defendant struggled with guards bringing him in and sat on the floor, his back to the judge, for much of the session.

After the stormy start, prosecutors put on the stand a member of Saddam's regime for the first time and produced documents, trying to link the former Iraqi leader directly to torture and executions that allegedly took place in a 1982 crackdown in the Shiite town of Dujail.

But the witness, Ahmed Hussein Khudayer al-Samarrai — the head of Saddam's presidential office from 1984-1991 and then again from 1995 until the fall of the regime in April 2003 — insisted he knew nothing about the events in Dujail.

"I am not fit to be a witness in this case," al-Samarrai told the court, bringing a smile from Saddam.

Prosecutors produced a 1984 document in Arabic allegedly signed by al-Samarrai stating that Saddam ratified "the execution of the Dujail detainees."

Asked whether the signature was his handwriting, al-Samarrai said he could not be sure. "I don't remember," he said. "I don't remember anything at all."

Twenty-six prosecution witnesses have testified since the trial began Oct. 19, many providing heart-wrenching accounts of torture and years of imprisonment in the crackdown launched in the wake of a 1984 attempt on Saddam's life in Dujail. But none directly linked Saddam to their ordeal.

In an apparent attempt to speed up the proceedings, investigating judges read short affidavits by 23 more witnesses Monday rather than having them take the stand. Their testimony resembled that of past witnesses.

Court officials have said prosecutors will put forward a series of upcoming witnesses and documents aimed at showing Saddam ordered or was aware of the killings and torture. A former intelligence official, Hassan al-Obeidi, was also due to testify Monday.

Another document the prosecutors produced was a 1987 memo from the presidential office's legal department saying two people sentenced to death in connection with Dujail had not been executed and suggesting those responsible for the "negligence" be investigated.

A note written in the margin, allegedly in Saddam's handwriting, approved the investigation but says the two people should be spared execution "because we cannot allow coincidence to be more compassionate than us."

Saddam and his seven co-defendants are on trial in the killing of nearly 150 Shiite Muslims in Dujail north of Baghdad. If convicted, they could face the death penalty by hanging.

Abdel-Rahman pressed ahead with the session after a challenging start resulting from his decision to force Saddam, his half-brother Barzan Ibrahim and the six other co-defendants to attend the session.

The defendants had vowed not to participate in the trial until the return of their lawyers. The defense team is boycotting the proceedings until chief judge Raouf Abdel-Rahman is removed, alleging he is biased against their clients.

Monday' session — the first in 11 days — opened with chants against President Bush, shouting matches, arguments and insults from Saddam and Ibrahim.

Even their dress signaled their defiance at being in the court. Ibrahim wore a white T-shirt, his head bare without the Arab headdress he insisted on wearing in past sessions as a mark of dignity. Saddam carried a Koran and wore a blue galabeya — a traditional Arab robe — with a black overcoat, a stark contrast to the tailored black suits he has worn to past sessions.

Saddam entered the court on his own, stood in front of his chair and shouted, pointing a finger, "Down with Bush. Long live the nation."

"Why have you brought us with force?" Saddam shouted at Abdel-Rahman. "Your authority gives you the right to try a defendant in absentia. Are you trying to overcome your own smallness?"

"The law will be implemented," Abdel-Rahman replied.

"Degradation and shame upon you, Raouf," Saddam yelled. Later, he called the investigating judges "homosexuals."

Ibrahim, shouting angrily, struggled with guards who led him into the courtroom by his arms. He argued with the judge, who ordered him to sit.

But Ibrahim, Saddam's former intelligence chief, refused and sat on the floor with his back to the judge. He remained there until al-Samarrai took the stand, when Ibrahim got back in his chair to see.

Abdel-Rahman took over as chief judge last month, taking a tough stance to impose order after his predecessor resigned amid criticism over tumultuous proceedings marked by frequent, profane outbursts by Saddam and Ibrahim.

The defense team walked out Jan. 29 after Abdel-Rahman threw one of their colleagues out of the courtroom. Saddam and three co-defendants were allowed to leave or were forcibly removed, and the judge appointed replacements for the defense lawyers.

In the following session Feb. 1, only three defendants attended. None showed up the next day and Saddam's lawyers have said they will continue to boycott the trial as long as Abdel-Rahman is on the bench.

The defense claims that Abdel-Rahman is unfit to try the case because he was sentenced to life in absentia in the 1970s for subversive activity. Saddam became president in 1979, but was Iraq's most powerful man for several years before that.