Denis Poroy, File, Associated Press
FILE - In this Aug. 30, 2007 file photo, Marine Corps Staff Sgt. Frank Wuterich arrives for his Article 32 Investigation Hearing at Camp Pendleton Marine Corps Base in San Diego County. Wuterich, the last defendant in the biggest and lengthiest criminal case against U.S. troops to arise from the Iraq war, is expected to stand trial this week, more than six years after his squad killed 24 Iraqi civilians in the town of Haditha, including unarmed women and children.

CAMP PENDLETON, Calif. — Military prosecutors say a sergeant saw the charred remains of a fellow Marine killed by a roadside bomb only moments before he instructed his squad to "shoot first, ask questions later" in what has become one of the Iraq war's most horrific episodes of civilian deaths.

Both the prosecution and defense agree the explosion that killed Lance Cpl. Miguel Terrazas in the Iraqi town of Haditha on Nov. 19, 2005, influenced Staff Sgt. Frank Wuterich's decisions that day.

The debate during the case's trial this month is over whether Wuterich reacted appropriately, or if he led his men on a vengeful rampage. In the end, 24 Iraqis were killed.

At least one of Wuterich's squad members is expected to testify for the prosecution Tuesday. It's the second day witnesses will take the stand before an all-Marine jury at Camp Pendleton.