BAGHDAD , Iraq ( CNN ) -- Allegations that five U.S. contractors detained inside Baghdad 's Green Zone were somehow involved in the death of another American contractor last month are `` completely false , '' a son of one of the detainees told CNN Sunday . In a CNN exclusive , video shows U.S. contractors taken into custody by Iraqi authorities . Four of the five detained contractors work for North Carolina-based Corporate Training Unlimited -- a security firm headed by Donald Feeney , who , along with his son , Donald Feeney III , has been detained , according to another son , John Feeney . A fifth contractor works in Baghdad for another company . `` We 're pretty sure they will be questioned there in the next couple of days and released with no charges , '' John Feeney said , adding the men appeared in court Sunday and were scheduled for another hearing Monday . CTU was founded by the elder Feeney , a former member of the elite anti-terrorist unit , the Delta Force , sources with knowledge of the case told CNN Sunday . The company in Fayetteville , North Carolina , has been operating in Iraq since 2003 , according to its Web site . Iraqi and U.S. personnel took the five into custody early Friday in connection with the killing of contractor James Kitterman , according to an Iraqi official involved in the investigation and another source with knowledge of the case . Three of them allegedly had direct involvement in the death , according to an Iraqi security source . None of the men have been charged . Kitterman was found bound , blindfolded and fatally stabbed in a car in the district , formally known as the International Zone , on May 22 . The 60-year-old Houston , Texas , resident owned a construction company that operated in Iraq . The U.S. Embassy in Baghdad confirmed that Iraqi authorities took five U.S. citizens into custody . The embassy said the men were not detained on suspicion of murder , but for an unrelated matter . The five were being held by Iraqi security forces Sunday at a jail inside the heavily protected Green Zone , the Iraqi official said . They have been in custody for three days . `` They have lawyers there on the ground with them , '' John Feeney told CNN . `` They have been there with them the whole time . We have people there who work for us who are bringing them food , clothes -- whatever they need . They 're being treated well , and the State Department and the FBI are also involved . '' The troops also confiscated weapons during the pre-dawn raid on the suspects ' firm , said the Iraqi official , who spoke on condition of anonymity . The four CTU detainees were identified by multiple sources as : Donald Feeney and Donald Feeney III ; Micah Milligan ; and Mark Bridges . John Feeney identified the fifth detainee as Jason Jones , who works for another company . A source close to the suspects , who asked not to be identified , said each of the five men insisted they have alibis that would clear them and that they are anxious to tell their stories to a judge . John Feeney said his father was `` not even in the country '' at the time of Kitterman 's killing . He was heading back from the Philippines to make arrangements after the death of another CTU employee at the time . The U.S. Embassy would not confirm the names of the detainees , citing privacy laws . But a spokesman said consular officials have visited with them and `` they appeared well . '' Embassy officials have been visiting them frequently , the Iraqi security source said . The U.S. State Department and the Iraqi government will negotiate to determine what happens next , according to the Iraqi security source close to the investigation who requested anonymity because of the sensitivity of the case . Iraqi jail workers are treating the five contractors very well and with respect , he said . The Feeneys had known Kitterman for six years from their time in the Green Zone and `` respected him , '' CTU spokeswoman Sarah Smith told CNN . `` Just being in the Green Zone for six years , they became very close , '' she said , adding , `` Everyone is deeply upset about the loss of Jim Kitterman and our deepest sympathy goes to his family . '' If the suspects are charged and referred to trial , the case would be sent to Iraq 's Central Criminal Court , the Iraqi official said . If that happens , it would mark the first time U.S. citizens go to trial in that country since the United States returned the nation 's government to the Iraqis . CNN 's Mohammed Tawfeeq , Phil Black , Jomana Karadsheh , Alan Duke and and Samira Simone contributed to this report .
NEW : Detainee 's son : ` ` We 're pretty sure they will be ... released with no charges '' Sources : Five contractors arrested in connection with murder of fellow U.S. contractor in Iraq . U.S. Embassy : Two contractors in custody in Iraq , but not on murder suspicion . Contractor John Kitterman found bound , blindfolded and fatally shot .