Defense Secretary Pete Hegseth on Wednesday acknowledged the U.S. military was investigating the incident. March 5 (Reuters) - U.S. military investigators believe it is likely that U.S. forces were responsible for an apparent strike on an Iranian girls’ school that killed scores of children on Saturday but have not yet reached a final conclusion or completed their investigation, two U.S. officials told Reuters. Reuters was unable to determine more details about the investigation, including what