MEXICO CITY, Dhu-AlHijjah 2, 1435, Sep 26, 2014, SPA -- An army officer and seven soldiers face disciplinary action for their participation in the killing of 22 people in rural southern Mexico, but the army remained mum on Friday on what roles they played, AP reported. The Mexican Defense Department said that the eight were involved in the June 30 incident in San Pedro Limon, an encounter that the military initially reported as a shootout but that a witness has described as a massacre. The National Human Rights Commission has requested a report on the arrests, investigator Marat Paredes said Friday. The army's Thursday night statement did not reveal the names of those detained nor their battalion. They were being held at a prison in Mexico City on charges of crimes against military discipline, disobedience and dereliction of duty." The statement said the military charges are being pursued "independently of the investigations that civil authorities are carrying out under their jurisdiction," leaving open the possibility of charges in civilian courts. President Enrique Pena Nieto said this week that the federal Attorney General's Office is also probing the incident. -- SPA 22:25 LOCAL TIME 19:25 GMT www.spa.gov.sa/w