One of four soldiers charged with pushing two Iraqis into the river, where one of them drowned, says he was ordered to do so and told what to say to officials looking into the death, an Army investigator testified Wednesday.

Spec. Terry Bowman said he "was told by his chain of command what version to give" investigators, Sgt. Irene Cintron of the Army Criminal Investigation Command said during a teleconference from Iraq as the military convened a hearing to determine whether the soldiers will be court-martialed.

Bowman said he had been ordered to push the men into the Tigris River, Cintron said.

It was not disclosed who gave the order. Three of the soldiers' commanders have received nonjudicial punishments for their roles in the incident. None of those punishments includes jail time.

Sgt. 1st Class Tracy E. Perkins, 33, 1st Lt. Jack M. Saville, 24, and Sgt. Reggie Martinez, 24, are charged with involuntary manslaughter in the Jan. 3 drowning of a man identified by family members in Iraq as Zaidoun Fadel Hassoun, 19.

Bowman, 21, is charged with assault for allegedly pushing the second man into the river at the same time. That man, a cousin of Hassoun named Marwan Fadel Hassoun, 23, survived the incident and described it to the Associated Press.

Marwan Hassoun said he tried to help his cousin swim to safety, only to lose his grip as the soldiers watched and laughed. "They were behaving like they were watching a comedy on stage," he said several weeks ago.

Perkins, Martinez and Bowman appeared at Wednesday's Article 32 hearing, which is similar to a civilian grand jury hearing. Saville's hearing is tentatively scheduled for Sept. 9. The four soldiers could face 51/2 to 261/2 years in prison if they are tried and convicted.

The soldiers' commanders, Lt. Col. Nathan Sassaman, Maj. Robert Gwinner and Capt. Matthew Cunningham, were punished this spring under Article 15, which allows punishments without a court proceeding or public record. Rep. Joel Hefley (R-Colo.) has asked for congressional hearings into why their cases were handled differently than those of the soldiers.

The soldiers are assigned to Fort Carson's 3rd Brigade Combat Team. The brigade is part of the 4th Infantry Division, based at Fort Hood, Tex.