A US soldier faces a court-martial Monday on charges that he participated in the execution-style slayings of four bound and blindfolded Iraqi detainees in the spring of 2007. Sgt. 1st Class Joseph Mayo, 27, is charged with premeditated murder, conspiracy to commit premeditated murder, and obstruction of justice in the incident that occurred while he was deployed to Iraq. He is the sixth of seven soldiers to face a court at the US Army's Rose Barracks since August, and the trial could last several days. No hometown for Mayo was provided by the Army. Last Month, a military court convicted Sgt. Michael Leahy, 28, of Lockport, Illinois, to life in prison with the possibility of parole after he admitted to the execution-style killing of one of the detainees and shooting another. He was acquitted of murder over a separate incident in Baghdad in January 2007.