A U.S. Army soldier who prosecutors assert hatched the plan for the execution-style slayings of four bound, blindfolded Iraqis by the side of a Baghdad canal pleaded not guilty to murder at his court-martial Monday.

Master Sgt. John Hatley, 40, was charged with premeditated murder, conspiracy to commit premeditated murder and obstruction of justice in the shootings that took place in spring 2007 in the Iraqi capital.

At the hearing, Hatley, dressed in his green formal uniform, entered his plea to Army judge Col. Jeffrey Nance. A jury of eight soldiers — a mix of officers and non-commissioned officers — will hear the case, which is expected to last through the week.

If convicted, Hatley could be sentenced to life in prison without the possibility of parole.

Prosecutor Capt. Derrick Grace said it was Hatley who decided to kill the four men and that he, along with two other men — Sgt. 1st Class Joseph Mayo and Sgt. Michael Leahy — walked to the canal where the four Iraqis were and shot them dead.

"In a few days I ask you to come back here to find the accused guilty of all charges," Grace said, addressing the jury.

Hatley's civilian lawyer, David Court, said the case was based only only testimony, not actual evidence. The bodies of the Iraqis have never been found.

"There is no autopsy, body or cause of death. There's no evidence, just testimony," he told the court. "There's no evidence that people died because of a shooting."

Hatley also faces charges of murder stemming from a separate incident in January 2007. A charge of conspiracy to commit murder in that case was dismissed on Monday.

Hatley, whose hometown has not been disclosed, is the last of five soldiers to face trial in the slayings of the four Iraqis. His court-martial at the U.S. Army Rose Barracks in southeastern Germany could last as long as a week, officials said.

On March 30, Mayo was sentenced to 35 years in prison with the possibility of parole after pleading guilty to premeditated murder and conspiracy to commit premeditated murder. He is expected to testify against Hatley.

According to testimony at previous courts-martial, at least four Iraqis were taken into custody in spring 2007 after an exchange of fire with Hatley's unit and the discovery of weapons in a building where suspects had fled.

The detainees were taken to the unit's base for questioning and processing, but there wasn't enough evidence to hold them for attacking the unit. Later that night, patrol members took the men to a remote area and shot them so that they would not be able to attack U.S. forces again, Mayo testified at his court-martial.

Mayo also testified that Hatley instigated the plan and that he and Leahy volunteered to help kill the detainees.

Leahy was convicted of murder and sentenced to life in prison with the possibility of parole after he admitted to the killing of one of the detainees and shooting another. He was acquitted of murder in the January 2007 incident.

Two more soldiers pleaded guilty to conspiracy to commit premeditated murder and were sentenced to prison last year. Two others had charges of conspiracy to commit premeditated murder dropped this year.

All were with the 1st Battalion, 18th Infantry Regiment, 2nd Brigade, 1st Infantry Division. The unit is now part of the Germany-based 172nd Infantry Brigade.