The three generals investigating the abuses at Abu Ghraib prison determined that six civilian contract employees participated in or failed to report abuse of prisoners, and they referred those individuals to the Justice Department for prosecution.

The employees worked for CACI International Inc., of Arlington, which provided interrogators at the prison, and Titan Corp., which provided translators. The report, which also said the Army failed to properly monitor contractors, provided the clearest view yet of the role contractors played in the prison abuses.

The report alleged that CACI interrogators used dogs to scare prisoners, placed detainees in unauthorized "stress positions" and encouraged soldiers to abuse prisoners at Abu Ghraib. Titan employees hit detainees and stood by while soldiers physically abused prisoners, according to the report.

"The use of contract interrogators and linguists at Abu Ghraib was problematic . . . from a variety of perspectives," the report said. The military was "unprepared for the arrival of contract interrogators and had no training to fall back on in the management, control, and discipline of these personnel."

The investigation found that about half of CACI's interrogators were not properly trained and that the military officer in charge of interrogations did not screen them before allowing them to conduct interrogations. In some cases, CACI interrogators supervised military personnel, which the company has said they were not authorized to do.

Investigators referred four contract employees to the Justice Department after finding they contributed to the abuse and two others for failing to report it.

The report, however, raised questions about how some contractors could be prosecuted. The CACI contract was managed by the Department of Interior. The report said that companies working under contracts not issued by the Defense Department may not be subject to the Military Extraterritorial Jurisdiction Act, which says military contractors are subject to criminal prosecution when operating outside the country if they are accompanying the armed forces.

CACI said in a statement that it is cooperating with the investigation and reviewing the report. "We regret that any CACI personnel are alleged to have engaged in inappropriate behavior."

An Army report released in May accused one CACI employee, Steven A. Stefanowicz, of being directly or indirectly responsible for the abuses. Stefanowicz was not named in yesterday's report. His lawyer repeated earlier assertions that his client had done nothing wrong.

While contending that Titan's contract produced "generally positive results," the report noted that on occasion linguists were removed from their positions for misconduct. The report cleared one Titan employee, who had been implicated in the internal Army report.

Titan said it was pleased one employee was exonerated and is cooperating with the investigation. "It goes beyond our imagination and violates all of our policies for any employee to participate or remain silent while the alleged abuses such as those at Abu Ghraib went on," Titan spokesman Wil Williams said. "If any of our employees have done anything wrong, we will take appropriate action."

The report said contract interrogators and linguists were involved in 16 of the 44 alleged abuses at the prison. According to the report, an unidentified CACI interrogator grabbed a prisoner from a vehicle, pulled him to the ground and dragged him to an interrogation booth as the prisoner tried to stand. The same CACI employee allegedly drank alcohol at the prison and refused to take orders from a military officer, saying, "I have been doing my job for 20 years and do not need a 20-year-old to tell me how to do my job."

Another CACI interrogator allegedly encouraged a soldier, Staff Sgt. Ivan L. Frederick, to abuse a detainee after a shooting incident at the prison, and did not stop Frederick from covering the detainee's mouth and nose, preventing him from breathing. Frederick has pleaded guilty to some charges of abuse of prisoners. The interrogator also allegedly used Frederick's presence as a threat to prisoners and used dogs during the roundup of detainees.

A third CACI employee is accused of humiliating a prisoner by shaving his head and beard and forcing him to wear red women's underwear.

The report also alleges that a civilian interpreter wearing a military uniform raped a 15- to 18-year-old male detainee while a female soldier took pictures. The incident's date and participants could not be confirmed, but the report said the description of the interpreter partially matches that of a Titan employee. The allegation is still being investigated, the report said.