A US marine filmed apparently shooting dead an injured Iraqi in a Falluja mosque last year may not be formally charged, according to media reports.
The US operation in Falluja reduced much of the city to rubble
Military investigators have concluded there is not enough evidence to prosecute over the shooting, US television network CBS news says.
However, the US military said the investigation had not been completed.
"The facts of this case are being thoroughly pursued to make an informed decision," a Marine statement said.
The US military set up an inquiry after footage of the killing was broadcast by the US network NBC.
The incident occurred during a search of a mosque by marines during the US assault on Falluja in November.
Kevin Sites, a news cameraman covering the operation, had entered the building with a squad of marines who were checking over a district fought for the previous day.
He caught on film one marine shooting an apparently unarmed, injured Iraqi. The soldier told investigators he thought he had seen the man moving.
Mr Sites said he had seen no movement apart from breathing from the Iraqi before he was shot.
The unnamed marine was withdrawn from combat while an investigation was carried out.
According to the CBS report, military investigators say the injured Iraqi might have been perceived as reaching for a weapon.
Legal experts have concluded that the situation was too ambiguous to ensure conviction, the network said.
However, the US Marine statement from Camp Falluja said the inquiry by the Naval Criminal Investigative Service was still ongoing.
The purpose of the investigation was to establish whether the soldier involved "acted in self-defence, violated military law or failed to comply with the Law of Armed Conflict", it said.
Marine spokesman Capt Dan McSweeney told AFP he had been informed by the Navy Criminal Investigative Service that the case was "still very much open".