BAGHDAD, Iraq (CNN) -- A former Iraqi intelligence officer who is critically ill testified before the Iraqi Special Tribunal in a special session Sunday in the case against former dictator Saddam Hussein, the chief investigative judge told CNN.The testimony came as the Iraqi Lawyers Union called on all Iraqi lawyers to refuse to appear before the tribunal until the killing of Sadoon al-Janabi -- an attorney for a Hussein co-defendant -- is solved.Wadha Ismail al-Sheikh, 55, testified from a Baghdad hospital in the first case against Hussein taken up by the tribunal.The trial, which began Wednesday but was adjourned until November 28, centers on the torture and killings of citizens 23 years ago in the town of Dujail, north of Baghdad.Chief Investigative Judge Raed Juhi said three judges and a prosecutor in the case went to the hospital to hear his testimony because, according to tribunal statutes, if a witness cannot appear in court, the court must go to the witness.Al-Sheikh's testimony away from courtroom was permitted because it was feared he may not survive until the trial resumes, according to a source close to the tribunal.Hussein and seven other defendants have pleaded not guilty to charges that they ordered the torture and killings of residents in the aftermath of a failed assassination attempt on the Iraqi leader July 8, 1982.A senior official in Iraq's intelligence service, al-Sheikh was appointed by Hussein's regime to investigate the assassination attempt, and his testimony is considered crucial in the case.Khamis al-Ubaidi, one of Hussein's attorneys, told CNN he and colleague Khalil al-Dulaimi did not attend Sheikh's testimony to protest al-Janabi's killing. Al-Ubaidi said any testimony given when defense lawyers were not present would not hold up in court.A representative in Baghdad of the New York-based group Human Rights Watch said tribunal statutes require the presence of defense attorneys at all testimony.Juhi told CNN the defense lawyers were invited to attend the session and were offered security to make the trip to the hospital.If they chose not to accept that offer, Juhi said, they could have participated in the session via video. He said the attorneys declined both options.Al-Sheikh, who was detained in 2003 by U.S. forces, was accused of embezzling from the Iraqi intelligence service in 1988 and was jailed for five years.Kamal Allaw of the Iraqi Lawyers Union told CNN the group called for a strike to take place Wednesday to condemn al-Janabi's slaying.His body was found in the Banook neighborhood of northern Baghdad on Thursday night, hours after gunmen burst into his office and abducted him. Iraqi police said he had been shot in the head. (Full story)Al-Janabi represented Awad Hamad Bandar, former chief judge of Saddam's Revolutionary Court, who is accused of having sentenced to death more than 140 residents of Dujail.Human Rights Watch said it had been told by several defense attorneys in the case that they would boycott proceedings until the security situation for the defense is addressed. The lawyers, the organization said, have asked that they be allowed to choose their own security detail, which would be licensed to carry arms and provide protection.Five U.S. soldiers among woundedAttacks in central and northern Iraq killed 10 people and wounded 32 others Sunday, officials said.In one of the deadliest strikes, a bomb in a parked car killed three people and wounded 14 others next to a Baghdad movie theater, police said. Two Iraqi police officers were among the dead and two other officers were injured. Three bombs struck the north-central city of Tikrit, killing Iraqi police Lt. Col. Haitham Akram and his three sons and wounding his wife at their house, an Iraqi police official said.Three children passing by the home on their way to school were wounded in the Qadisiya neighborhood bombings, the official said.In other attacks Sunday, gunmen shot and killed an Iraqi police officer in a market in central Baquba, north of Baghdad, a Baquba police official said. Shortly after the shooting in Baquba, gunmen shot and killed Shiite cleric Sheik Ahmed Abdul Rahman in Buhriz, a town about six miles (10 kilometers) to the south.In the Iskan neighborhood of eastern Kirkuk in northeastern Iraq, a suicide car bomb targeting a U.S. military convoy killed a civilian and wounded seven others, said Kirkuk police chief Maj. Gen. Torhan Abdul Rahman. Three separate roadside bombs targeted U.S. troops in central Baghdad on Sunday, said Sgt. David Abram, a U.S. military spokesman with the 3rd Infantry Division. The attacks injured five soldiers.The number of U.S. troops killed in the Iraq war stands at 1,993, according to U.S. military reports.Other developmentsFour American contractors were killed in an attack north of Baghdad on September 20, the U.S. military said Sunday. Another two Americans were injured in the attack near Duluiyah, said Maj. Richard Goldenberg, spokesman for Task Force Liberty, 42nd Infantry Division. U.S. contractor KBR, a subsidiary of Halliburton Co., said three of its employees were killed that day, said Halliburton spokeswoman Cathy Mann.Two bodies were found Saturday in Diyala province in the southern suburbs of Baquba, police said. Police have not identified the bodies, but the victims' ages were estimated between 25 and 30 years old. They were shot in the head with their hands tied behind their backs, police said.CNN's Enes Dulami, Nic Robertson and Mohammed Tawfeeq contributed to this report.