Italian prosecutors have called for a US soldier to stand trial for the killing of an Italian intelligence officer in Baghdad in 2005.
Nicola Calipari's death was mourned across Italy
Nicola Calipari, 51, was shot dead at a US roadblock while escorting Italian journalist Giuliana Sgrena, who had been released by kidnappers in Iraq.
Italy and the US government disputed the circumstances of his death.
Italian prosecutors want a US marine, identified as Mario Lozano, to go on trial for the March 2005 killing.
US military: Car approaches checkpoint at high speed
Troops attempt to tell driver to stop with arm signals, lights and warning shots
Soldiers shoot into engine
Italian government: No warning signs to motorists about impending checkpoint
Car not speeding and did not accelerate after warning shots
Proper inquiry impossible because vehicles removed and army logs destroyed just after shooting
Last week Mr Lozano's court-appointed lawyer, Fabrizio Cardinali, said he expected his client to be tried in absentia for murder and attempted murder.
Last year Italy published a report into the shooting which conflicted with the US version of events.
The report blamed the troops' stress and inexperience, and said the US authorities should have signalled that there was a checkpoint on the road.
The report denied the US assertion that their military command in Baghdad was unaware of the Italian mission to secure the hostage's release, pointing out that the Italians had been allocated secure accommodation in an American-controlled area.
It said that the Italian car had been travelling at 40-50km/h, while the American version said it was going at about twice that speed.
The Americans insist that the car was going too fast and alarmed their soldiers.
The Italian magistrates say they are concentrating on ballistic evidence from the car. They say it was hit with three rounds; the second round which killed the officer was fired, they say, as the car was slowing down.
Their decision on Monday is likely to put further strain on relations between the two countries, the BBC's Christian Fraser reports from Rome.
The new Italian government has already stated its intention to withdraw troops from Iraq later this year and some of the comments they have made on the Iraq situation are said to have seriously irritated senior White House officials, our correspondent adds.