The lawyer for a U.S. soldier accused of masterminding the execution of four Iraqi prisoners in 2007 brought in more witnesses Wednesday as the last of five courts-martial continued.

David Court, the lawyer for Master Sgt. John Hatley, has argued there is no physical evidence showing that the victims were shot and killed execution style in Baghdad because the bodies have never been found.

Court has argued that Army prosecutors are relying only on circumstantial evidence and conflicting testimony from this week and other courts-martial that resulted in murder convictions of two other soldiers.

Hatley pleaded not guilty Monday to premeditated murder, conspiracy to commit premeditated murder and obstruction of justice in the incident that took place in spring 2007. He also faces murder charges from a separate January 2007 incident.

Army Judge Col. Jeffrey Nance and a jury of a mix of eight officers and noncommissioned officers are hearing the case, which is expected to last through the week.

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

Army prosecutors have alleged that Hatley and two other members of his patrol took the four Iraqi men to a remote area in Baghdad's West Rasheed neighborhood, shot them in the head and dumped their bodies into the canal.