CAMP PENDLETON -- A Marine 1st sergeant testified Wednesday morning that he believed the 2005 slaying of two dozen Iraqi civilians in the city of Haditha required an immediate investigation.

The high number of fatalities was "shocking," 1st Sgt. Albert Espinosa said, adding that soon afterwards he became increasingly frustrated that no formal review appeared to be taking place.

Espinosa's testimony came at the start of second day of a hearing for Capt. Randy Stone, a battalion lawyer charged with dereliction of duty for not conducting a full-scale investigation of the incident.

"I just couldn't believe it, sir," Espinosa said in response to a question from Lt. Col. Paul Atterbury, one of three prosecutors handling the case against Stone. "It was just too many casualties."

Stone, 34, is one of four officers from Camp Pendleton's 3rd Battalion, 1st Marine Regiment charged with failing to fully investigate an alleged violation of the law of war.

Three enlisted men from the battalion's Kilo Company face homicide charges for the deaths that occurred after a roadside bomb destroyed a Humvee, killing one Marine and injuring two others. The storming of the homes followed the bombing as the Marines suspected insurgents were using them as a base of attack.

As the company's 1st sergeant, Espinosa testified that one week after the Nov. 19, 2005, incident, he initiated a conversation with Stone at the battalion's command center in Haditha because, "I wasn't happy with the answers I was getting. I thought we need to do an investigation."

Stone told him that a probe was taking place at the battalion level, Espinosa said, later adding that a sergeant major also said it was being addressed at a higher level.

Espinosa said he thought that statements should have been taken from the Marines linked to the killing because that was what had happened in a 2003 incident when a 12-year-old Iraqi girl was slain. Espinosa assisted in that investigaton

On Tuesday, another 1st lieutenant who ordered the assault of a group of homes where a majority of the civilians died from grenade and gunshot wounds testified that he believed the actions fell with the rules of engagement and that no investigation was necessary.

Under questioning by Stone's attorney Charles Gittins, Espinosa said he was unaware of what reports were being filed at the battalion level.

Gittins also said a regimental commander had determined that the civilians deaths were "collateral damage" and that no investigation was necessary. The defense attorney's statement made in the course of questioning Espinosa went unchallenged by prosecutors.

Later today, one of the men originally charged with homicide for the civilian killings, Sgt. Sanick Dela Cruz, is expected to testify. The charges against him were dropped last month after the Marine Corps said his testimony outweighed his involvement in the slayings.

The case against Stone is the first to reach court in the Haditha incident. At the conclusion of the hearing, the Marine Corps officer presiding over the testimony will write a report recommending whether he believes Stone should stand trial.

See Thursday's North County Times for a full report on Wednesday's testimony.

Contact staff writer Mark Walker at (760) 740-3529 or mlwalker@nctimes.com.