VILSECK, Germany, Dec. 3  -- A U. S. Army sergeant told his men four Iraqi detainees were killed to avenge the deaths of three members of his unit, soldiers testified Wednesday.

1st Sgt. John Hatley, Sgt. Joseph Mayo and Sgt. Michael Leahy Jr. -- who were then members of Company A, 1st Battalion, 18th Infantry Regiment -- are accused of shooting detainees before dumping their bodies in a Baghdad canal in March or April 2007, Stars and Stripes reported Wednesday.

Several members of the company who were at the canal when the killings occurred testified after assurances the federal government would grant them immunity from prosecution.

Sgt. Daniel Evoy, who said he witnessed the execution of one of the Iraqis through the hatch of his vehicle, said three Company A soldiers -- Sgt. Mario Kawika De Leon, Spc. Marieo Guerrero, and Staff Sgt. Karl Soto-Pinedo -- were killed in action near the time of the incident.

"I think the first sergeant got hit hard by Staff Sgt. Soto being killed. He was pretty much his go-to guy. I think Hatley had resentment toward those guys (the detainees)," he testified at Mayo's Article 32 hearing in Germany. (UPI)