Lawyers representing Saddam Hussein have said they are suspending any contact with the tribunal trying the former Iraqi leader over safety fears.
Gunmen abducted Mr Janabi from his office
The group says contacts will be frozen until security arrangements improve.
The move follows last week's abduction and murder of Sadoun Nasouaf al-Janabi, a lawyer representing one of the ousted Iraq president's co-defendants.
It raises fresh questions as to whether the former leader, whose trial opened last week, will receive a fair hearing.
He is being tried for crimes against humanity.
"We, the defence team that groups over 2,000 Iraqi lawyers... have decided to completely halt dealing with the tribunal," a statement signed by Saddam Hussein's lead lawyer Khalil Dulaimi read.
The statement cited "the deteriorating security situation and its repercussions on the work of the Iraqi lawyers, and the continuous threats against their lives and their families that were demonstrated by the killing of the martyr Sadoun Janabi".
Saddam's trial was adjourned until 28 November
Mr Janabi was seized by gunmen at his office in the Iraqi capital, Baghdad, last Thursday evening.
On Friday his body was found outside the city's Firdous mosque. He had been shot in the head.
Mr Janabi was acting for one of Saddam Hussein's co-defendants, Awad Hamed al-Bandar, a former top judge.
Saddam Hussein is charged with the killing of more than 140 men in the mostly Shia town of Dujail after a failed assassination attempt against him.
The former Iraqi leader and his co-defendants have pleaded not guilty to the charges.
The trial was adjourned until 28 November but the defence lawyers are now asking for a complete freeze on the proceedings until their demands are met.
Along with an independent investigation into Mr Janabi's death, the protesting lawyers are also demanding that Saddam Hussein's defence lawyers and their families be given protection, including 15 bodyguards each.
They also asked for permission to carry weapons and to be given passes to get them through Iraqi and US security checkpoints.
There had been tight security at the court as the trial of Saddam Hussein and his seven co-defendants opened on Wednesday 19th October.
Four of the five judges and most of the prosecution lawyers have remained anonymous for safety reasons.
The names of the chief judge and the top prosecutor were the only ones revealed.
But the defence team's identities were not kept secret, and Saddam Hussein's top lawyer, Mr Dulaimi, says many had been threatened.