An investigation by the U.S. Southern Command into allegations of prisoner abuse at Guantanamo Bay detention center has concluded that "insufficient evidence exists to substantiate the paralegal’s allegations." But Lieutenant Colonel Colby Vokey, the superior officer to the Marine sergeant who filed the allegations, called the investigation "outrageous." "I am aware that the investigators interviewed only the suspects and some witnesses but did not interview any detainees or potential victims," he told ABC News. "Failure to interview those who may have been subjected to abuse is indicative of an incomplete investigation." As first reported on "The Blotter" on ABCNews.com, Heather Cerveny (pictured), 23, a Marine Corps sergeant, who spent a week on the base last September working as a legal aide to Lt. Col. Vokey, said she was "shocked" to hear several guards from different parts of the base openly speak of mistreating prisoners. THE BLOTTER RECOMMENDS Video World News: Beatings Are ‘Common’ at Gitmo Blotter White House Ceding Legal Ground in Detainee Battle? Click Here to Check Out the Latest Brian Ross Slideshows One said, "I took the detainee by the head and smashed his head into the cell door," she told ABC News in October after filing a sworn affidavit with the Pentagon Inspector General. Another "was telling his buddy, ‘Yeah, this one detainee, you know, really pissed me off, irritated me. So I just, you know, punched him in the face.’" The following investigation by SouthCom, which oversees military activities in the Caribbean and Latin America, looked into Cerveny’s account and another filed by a civilian employee on the base that recounted a conversation between a female guard and a male interrogator on a training range. After interviewing 20 suspects and witnesses and combing through "three JTF-Guantanamo records systems used to trace detainee-guard interaction," investigators determined, "The evidence did not support any of the allegations of mistreatment and harassment." Click Here for Full Blotter Coverage. Amongst the recommendations issued by the investigating officer but ultimately rejected by the SouthCom commander following the investigation was "that disciplinary or other action be taken against Sergeant Cerveny," which Lt. Col Vokey says is the most "outrageous part of the investigation." "The interview of her [Sgt. Cerveny] was ridiculous and oppressive," he said. "The investigating officers, a colonel and a captain, walked straight into her office with the intent to accuse her of a crime before she even opened her mouth. The colonel already had the form in his hand to read her her rights and accuse her, before the interview started." Lt. Col. Vokey says this investigation sets a dangerous precedent for all officers who find themselves in a position to report suspected criminal activity. "This was outrageous and sends a dangerous message to all our service members: you’d better not report anything that goes on at Guantanamo Bay, or you’ll be threatened or charged with a crime." Read the press release from United States Southern Command.