CAMP PENDLETON, Calif. -- Two Camp Pendleton-based Marines were ordered released from jail by a federal judge in Riverside despite their refusal to testify before a grand jury probing the alleged killing of four Iraqi prisoners by Marines during the 2004 battle for Fallujah, it was reported Friday.

Sgt. Jermaine Nelson and Sgt. Ryan Weemer are still in contempt of court, said U.S. District Judge Stephen Larson. But he also said that keeping them behind bars would not convince them to testify, and ordered them released on Thursday, the Los Angeles Times reported.

The Marines' attorneys had argued they would never testify before the grand jury, which is looking at the actions of former Sgt. Jose Nazario.

Nazario, who is no longer in the Marines, is charged in federal court with voluntary manslaughter in the killing of two Iraqi captives during fighting in Fallujah in November 2004. He has pleaded not guilty to the charges.

Nazario was not on active duty when the Fallujah investigation began. By law, the U.S. Attorney's Office has authority to charge former military personnel for alleged crimes committed during their service, the newspaper reported.

Nelson and Weemer are each charged in military court related to the alleged killing of Iraqi prisoners. Both had expressed concern that their grand jury testimony could be used by military prosecutors. Nelson also refused to testify because Nazario saved his life in Iraq, The Times reported.

Weemer had been in the San Bernardino jail since June 12, Nelson since June 24. Nelson had earlier spent eight days in jail before being released by a judge in Los Angeles, the newspaper reported.

Joseph Low, Nelson's attorney, said Judge Larson should be praised for taking into account "the service that these Marines have given to their country," The Times reported.

The jailing of Weemer and Nelson had infuriated some active-duty and retired Marines, according to the newspaper.