Sentence:  <WSD>LOD</WSD> investigations are usually a result of a soldier or other personnel being killed or injured, and the investigation is necessary to determine if the cause was in the line of duty, or if the actions that caused the casualties or injuries were a result of neglect or misconduct and not in the line of duty. 
Meaning of the word marked with <WSD> tags:  Line of duty; an official determination of whether something occurred in the line of duty.