A federal magistrate ruled Monday that four Navajos charged in the slaying of two tribal police officers will face trial in U.S. District Court, but took under advisement a motion to release the defendants on bail.

U.S. Magistrate Ronald Boyce ruled there is probable cause to try Thomas Cly, Marques Atene, both 22; Vinton Bedonie, 31; and Ben Atene Jr., 24, on first-degree murder charges and aiding and abetting in the deaths of Navajo police officers Andy Begay and Roy Lee Stanley.But defense attorneys said the government's case is based in "oblique innuendo" from witnesses who were also involved in the killings of the officers, found dead in a smoldering police vehicle near Monument Valley, last December.

FBI Special Agent James Downey testified during Monday's preliminary hearing that three witnesses said all four were involved in shooting the officers at a drinking party near Goulding, San Juan County.

The four then transported the officers and their police vehicles 13 miles to Copper Canyon near

Lake Powell and set their vehicles, with the officers inside, afire.

The two officers died not of gunshot wounds but of smoke inhalation and burns, an autopsy showed. A Stanley relative burst into tears and ran from the courtroom when Downey testified about the cause of death.

But Vinton Bedonie fired the shots at both officers and Thomas Cly lit the fire that burned the officers' bodies beyond recognition, the FBI learned during an interview with three witnesses, Downey said.

Stanley was shot while wrestling on the ground with the four defendants after an argument broke out at the drinking party he was investigating, Downey said, quoting from witnesses' statements.

"They really hated Roy Lee (Stanley) for breaking up their parties," Downey said a witness told the FBI.

Stanley was handcuffed and led to his police vehicle where he was forced to radio Begay, telling him to come to the drinking party.

Stanley was then shot and loaded in his police vehicle. Begay was shot in the back when he arrived and also placed in the vehicle.

The officers, apparently still alive, were driven by the four, plus others, including the witness who provided the FBI with a probable-cause statement, to Copper Canyon where the police vehicles became mired in the sand.

There, Cly doused the vehicles and the bodies with gasoline from a five-gallon can and set flame to the vehicles, which "went up with a swoosh," Downey said, again quoting from a witness statement.

But attorneys representing the four defendants told the Deseret News the government's case rests on statements from at least one witness who was involved in the slayings.