Two more U.S. contractors have been released on bond but face an ongoing investigation, the embassy said Saturday, the latest development in the first case of Americans facing Iraqi justice under a new security pact, AP reported. Two other Americans remained in custody while a fifth was freed on bond Thursday. U.S.-backed Iraqi forces detained the five Americans on June 3 in connection with an investigation into the stabbing death of a fellow contractor. The two Americans were released on bond late Friday, a day after a third contractor was freed, U.S. Embassy spokesman James Fennell said. All five remain under investigation, but Iraqi authorities told embassy officials that «the nature of the ongoing investigation does not involve the James Kitterman homicide but another unrelated matter,» according to Fennell. Kitterman, 60, of Houston, was found dead in his car on May 22 in Baghdad's protected Green Zone. He had been blindfolded, bound and stabbed. U.S. and Iraqi officials have said the five detained Americans were not accused in Kitterman's death but were detained in a raid that was part of the investigation into the killing. Iraqi government spokesman Ali al-Dabbagh said earlier this week that the five contractors have been cleared of any link to the slaying but separate investigations were under way on drug and weapons charges. Corporate Training Unlimited, a Fayetteville, North Carolina-based security company, confirmed that its owner, Donald Feeney Jr., was freed on Thursday. Feeney's son, Don Feeney III, was one of the two released Friday, according to his brother, John Feeney, who wasn't sure of the name of the second contractor released. «Not knowing is the biggest thing. We were certain they were innocent, but going through the process and waiting was tough,» John Feeney said by phone from Fayetteville on Saturday. Feeney said he is anxious to see the other two contractors released. «We're still not exactly sure why they are doing one here and one there, but we should have all of them out in day or two,» he said. A U.S.-Iraqi security pact that took effect on Jan. 1 lifted the immunity that had been enjoyed by American contractors in Iraq for much of the six-year war. The move was provoked by outrage over a deadly September 2007 shooting in Baghdad involving another North Carolina security firm, Blackwater Worldwide, now known as Xe. The agreement also set a timeline for the withdrawal of American forces from urban areas by the end of this month and from the entire country by 2012.