A defense lawyer in Saddam Hussein's (search) mass murder trial has been found dead, his body dumped near a Baghdad mosque with two gunshots to the head, police and a top lawyers union official said Friday.

In other violence, four U.S. service members were killed in two attacks Thursday, the U.S. military said. Three Marines died when a bomb hit their patrol in the village of Nasser wa Salam, 25 miles west of Baghdad (search), and other American troops clashed with gunmen, killing two insurgents and capturing four, the military said.

An American soldier was killed in the northwestern town of Hit by "indirect fire," a term that usually means a mortar or rocket attack, the military said.

Nineteen Americans have been killed in the past week. The latest deaths brought to 1,992 the number of members of the U.S. military who have died since the beginning of the war in 2003, according to an Associated Press count.

The lawyer, Saadoun Sughaiyer al-Janabi (search), was abducted from his office by 10 masked gunmen Thursday evening, a day after he attended the first session of the trial, acting as the lawyer of one Saddam's seven co-defendants.

Al-Janabi's body, with two bullet shots to the head, was found hours later on a sidewalk near Fardous Mosque in the eastern neighborhood of Ur, near the site of his office, said police Maj. Falah al-Mohammedawi.

Diaa al-Saadi, senior official in the lawyers syndicate, said al-Janabi's family confirmed to him that he was dead. "This will have grave repercussions. This will hinder lawyers from defending those held for political reasons," al-Saadi warned.

Al-Janabi's family, reached by phone by The Associated Press, declined to comment.

The killing was the first setback for a tribunal that has been held under tight security.

Heavy protection was provided for prosecutors and judges in the Saddam trial, on the theory that they were likely targets of pro-Saddam insurgents seeking revenge. Their names have not been revealed and their faces were not shown in the broadcast of Wednesday's opening session — with the exception of the presiding judge and the top prosecutor, whose identities were revealed for the first time just before the trial.

But security measures do not appear to have been extended to the defense lawyers for Saddam and his seven co-defendants. Their identities have been known, although most of them have not been prominent in the press.

Al-Janabi was defending Awad Hamed al-Bandar (search), the former head of Saddam's Revolutionary Court. Saddam and the seven top officials from his Baath regime face a possible death sentence if convicted in their trial on charges of murder and torture in a 1982 massacre of 148 Shiites in the town of Dujail (search).

Saddam's chief lawyer, Khalil al-Dulaimi, said after the kidnapping that defense lawyers have received many threats in past weeks by e-mail, cell phone text message and by telephone. He did not specify if they were from Saddam opponents angry at their defending Saddam's regime or from Sunni supporters angry that they were participating in the trial at all.

"We condemn this killing, which does not serve the interests of the trial or of the political process," said government spokesman Laith Kubba.

"We do not know who was behind this operation. Is it designed to hinder the trial process of is it a case of vendetta? We don't know," he said.

During Wednesday's session, al-Janabi, with silver hair and a dark black mustache, sat with the 12 other defense lawyers in two rows of desks to the right of their clients. Al-Janabi was in the front row and spoke at least once during the session, but did not stand out in the proceedings as did al-Dulaimi or others who spoke more often or more combatively with the judge.

He was abducted from his office in the Shaab district, which for months has been the scene of attacks by insurgents and violence between its mixed population of Sunnis and Shiites.

In April and July, two deadly suicide car bomb attacks hit army posts there. In May, gunmen killed a Shiite Muslim cleric, and the bullet-ridden bodies of two missing Sunni clerics who had been kidnapped there were found. On Aug. 12, members of a Shiite Muslim militia freed four hostages from a home there.

The district is close to Sadr City, a large mostly Shiite and poor area of Baghdad that is a stronghold of the Shiite Mahdi Army militia. On Thursday, Rory Carroll (search), 33, the Baghdad correspondent for the British newspaper The Guardian was released unharmed in Sadr City, a day after being kidnapped there by gunmen. A group of Sadr City residents reportedly raided the area where he was being held by criminals and freed him.

Saddam and his co-defendants pleaded innocent in the trial, which was adjourned until Nov. 28.

But in the meantime, the court will hear its first prosecution witness: a Wadah Ismail al-Sheik, a bedridden cancer patient who was director of the investigation department at Saddam's feared Mukhabarat intelligence agency at the time of the Dujail massacre. Court officials will go Sunday to his hospital to take his testimony, court officials said on condition of anonymity because of the sensitivity of the subject.

Iraqis, meanwhile, are still waiting to know the outcome of the Oct. 15 constitutional referendum. Initial returns indicated it had passed, but electoral officials are conducting an audit of unusually high "yes" votes in some areas to ensure there are no irregularities — amid Sunni Arab accusations of fraud. The review has delayed the final results, expected early next week.

In other violence Friday in Baghdad, drive-by shootings killed four police commandos, an army captain and a mosque preacher.

The bodies of three policemen who had been blindfolded and shot in the head by insurgents near the Jordanian border were brought Baghdad, police said. Another body of a civilian who had been killed by unknown captors was found in central Baghdad, police said.

Fighting also continued in Operation River Gate (search), an offensive by 3,000 U.S. and Iraqi forces that began Oct. 4 in and around Haditha, 140 miles northwest of Baghdad.

Associated Press Television News video showed U.S. tanks on the outskirts of Haditha, helicopters circling overhead and American soldiers moving through the city Thursday. Crackles of gunfire could be heard. In Baghdad, the U.S. military said Friday that it had no new information about the offensive or casualties in the fighting.