The brother-in-law of Mohammad Oreibi al-Khalifa, the new chief judge in the genocide trial of Saddam Hussein, has been shot dead.
Chief Judge Oreibi al-Khalifa was appointed last week
Gunmen opened fire on Kadhem Abdul Hussein's car in the mainly Sunni suburb of West Baghdad on Thursday evening, police said.
Mr Abdul Hussein was killed outright and police said his son was injured.
Three defence lawyers working on the trials of the former Iraqi leader have been murdered since last October.
Mr Abdul Hussein, a Shia, was the husband of Mr Khalifa's sister.
A police source told Reuters news agency the attack happened in a large Sunni Arab neighbourhood in the Iraqi capital at 1900 local time (1500 GMT) on Thursday.
The BBC's Jim Muir, in Baghdad, says the assumption is that it was a deliberate killing and the gunmen knew the identity of their target.
Mr Khalifa, also a Shia, was appointed to the Saddam Hussein trial last week after the government asked the court to sack his predecessor over concerns about his neutrality.
Chief Judge Abdullah al-Amiri had sparked controversy by saying the ex-leader had not been a dictator.
All involved in the trials of the former Iraqi leader - including judges, lawyers and witnesses on both sides - are regarded to be at high risk.