The plea from Staff Sgt. Frank Wuterich, 31, came in the middle of his court-martial at Camp Pendleton. Charges of manslaughter and assaulted were dropped as a result of the plea agreement.Misdemeanor dereliction of duty is punishable to 90 days in custody and a reduction or forfeiture in pay.Wuterich is scheduled to be sentenced Tuesday at Camp Pendleton."Staff Sergeant Wuterich believed this was the right and honorable thing to do," Wuterich's lead attorney, Neal Puckett, told the North County Times.Wuterich's plea was anticipated last week, but his court-martial resumed when negotiations apparently fell through.Several prosecution witnesses gave testimony backing Wuterich's position that he believed his squad was under attack when the killings occurred.Wuterich was accused in the deaths in Haditha, Iraq, on Nov. 19, 2005, after a roadside bomb killed a member of his squad. He was assigned to 3rd Battalion, 1st Marine Regiment, 1st Marine Division at the time of the incident.The single father of three girls said he believed five men who were killed when they pulled up in a car represented a threat after the roadside bombing.Nineteen other people -- including six children and four women -- were killed in three houses."The decisions he made that day led to an outcome that was tragic and regrettable but they were not criminal," Puckett told the North County Times.Eight Marines were charged in connection with the deaths, including four officers and four enlisted men. All of their case were resolved.