The biggest U.S. criminal case involving civilian deaths in the Iraq war begins its fourth day in court Friday with mounting testimony that Marines initially considered the killings of 24 Iraqis an unfortunate, but legitimate, consequence of urban combat.

Witnesses have testified at a preliminary hearing for Capt. Randy W. Stone that the killings of 24 Iraqi civilians came on a brutal day of combat on Nov. 19, 2005 in Haditha. They said they did not see any need for an investigation at the time.

Stone is one of four officers charged with dereliction of duty for failing to investigate the killings. Three enlisted Marines are charged with murder.

An intelligence officer and an operations officer were among those expected to testify Friday.

The attack occurred after a roadside bomb struck a Humvee convoy, killing one Marine and injuring two others. In the aftermath, Marines shot five Iraqis standing by a car and went house to house looking for insurgents, using grenades and machine guns to clear houses.

Maj. Gen. Richard A. Huck, the top general in charge of Marines in Iraq's Al Anbar province when the killings occurred, testified Thursday that he knew about the deaths the day they took place, but considered them simply a "truly unfortunate" consequence of war at the time.

"I had no information that a law of armed conflict violation had been committed," he said by video link from the Pentagon.

Huck said he initially saw no reason to investigate the killing of women and children by troops, and said he didn't learn about allegations that civilians were intentionally targeted until three months later when a Time magazine reporter raised questions.

Stone's attorney, Charles Gittins, called Huck to testify in an attempt to show Stone did nothing wrong because Marines throughout the command chain knew about the killings but agreed not to order an investigation because the deaths were deemed to have been lawful.

On Wednesday, a Marine sergeant testified that his squad leader, Staff Sgt. Frank Wuterich, shot five Iraqi men as they stood with their hands in the air and then told comrades to lie about it.

The hearing is part of an Article 32 investigation, the military's equivalent to a grand jury proceeding. Maj. Thomas McCann, the investigating officer, will hear evidence and recommend whether the charges should go to trial.