BAGHDAD, Iraq (CNN) -- Five U.S. contractors appeared in an Iraqi court Monday and were told to expect a decision Tuesday on whether they would be freed or stand trial, a source close to the suspects told CNN.
In a CNN exclusive, video shows U.S. contractors taken into custody by Iraqi authorities.
The reason for the contractors' detention remained unclear.
The five were initially told they were being held in connection with the death last month of another contractor, James Kitterman, said the source, who asked not to be identified. But on Monday, according to the source, the men were told they are being held on suspicion of having unregistered weapons, although they were asked about their activities around the time Kitterman was killed.
However, Iraqi government officials told CNN Monday the five are detained as suspects in connection with Kitterman's slaying.
None of the five has been charged with a crime.
Kitterman was found bound, blindfolded and fatally stabbed in a car in Baghdad's Green Zone on May 22. The 60-year-old Houston, Texas, resident owned a construction company that operated in Iraq.
The Green Zone is the high-security area in central Baghdad which contains the U.S. Embassy and key Iraqi government buildings. Access to the area, formally known as the International Zone, is tightly controlled.
"After this murder inside the Green Zone, a joint investigation committee from U.S. and Iraq sides has been formed to investigate this incident," Iraqi Interior Ministry spokesman Abdul Karim Khalaf told CNN, "and this committee managed to collect a number of indications that those five are linked to this murder."
Iraqi government spokesman Ali al-Dabbagh also said the men were detained based on information linking them to the Kitterman slaying. The men appeared before an Iraqi investigative judge on Sunday and Monday, and will appear again Tuesday, he said. The judge has questioned them and will continue to do so, he said.
Under Iraqi law, after a person is detained, an investigative judge questions the accused and assesses the evidence. Once the judge completes the investigative phase, he decides whether there is sufficient evidence, and either refers the case to trial or dismisses it.
If the judge rules the U.S. contractors are being held in connection with a murder investigation, they could be held indefinitely while the investigation continues. Murder is punishable by death in Iraq.
"If the evidences of the investigation are enough to charge and convict them," Khalaf said, "then they will receive a fair trial and they will have all the right to [defend] themselves and to appoint as many lawyers [as] they like, either Americans or Iraqis."
The United States has not requested custody of the men or their release, al-Dabbagh said, and a joint U.S.-Iraqi committee is following the investigation.
The contractors were taken into custody Wednesday in a pre-dawn Green Zone raid executed by Iraqi and U.S. personnel, according to an Iraqi security source, who requested anonymity because of the sensitivity of the case. They were transferred to their current prison within the Green Zone on Friday, leading to erroneous reports they had been detained on Friday.
During the raid, troops also confiscated weapons, the Iraqi source said.
The U.S. Embassy in Baghdad said Sunday that the men were not detained on suspicion of murder, but for an unrelated matter. On Monday, an embassy spokesman added that the raid in which they were seized was part of the Kitterman murder investigation, and that during the search officials found evidence of that unrelated matter on which the five are detained.
The embassy would not elaborate on that matter or confirm the contractors' identities. However, multiple sources identified four detainees as Donald Feeney and Donald Feeney III; Micah Milligan; and Mark Bridges. John Feeney, son of Donald Feeney, identified the fifth detainee as Jason Jones.
According to an embassy spokesman, the search Wednesday was an Iraqi operation, and FBI representatives were present at the request of Iraqi authorities. He would not comment when asked if the FBI or any other American agency was still involved in the investigation.
John Feeney denied that the contractors were involved in the death of Kitterman, saying the allegations against them are "completely false." He said his father was "not even in the country" at the time of Kitterman's killing.
The source close to the suspects said Sunday that each of the five men insisted they have alibis that will clear them and they are eager to tell their stories to a judge.
Four of the five detained contractors work for Fayetteville, North Carolina-based Corporate Training Unlimited -- a security firm headed by the elder Feeney. Jones works in Baghdad for another company.
The Iraqi source said the five were being held in a separate holding area and not with Iraqi detainees, but spend time in a courtyard with other detainees.
A U.S. Embassy spokesman said consular officials have visited with the detainees and "they appeared well." Embassy officials have been visiting them frequently, an Iraqi security source 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, it would mark the first trial of U.S. citizens in Iraq since the United States returned the country's government to the Iraqis. Khalaf said he considers the case significant because of that.
CNN's Mohammed Tawfeeq, Phil Black, Jomana Karadsheh, Alan Duke, Matt Smith and Samira Simone contributed to this report.