Ben Atene Jr. was not the "principal actor" in the slaying of two Navajo tribal officers, but his involvement makes him as guilty as two men already convicted in the slayings, a federal prosecutor said in opening arguments Wednesday.

But a defense attorney countered that no physical evidence linked Atene, 24, to the deaths of officers Roy Lee Stanley and Andy Begay and the testimony of prosecution witnesses would prove to be inconsistent and unreliable.The opening arguments came in Atene's retrial on two-counts each of first-degree murder, assault with the intent to commit murder and use of a firearm in commission of a crime. The officers' charred bodies were found in their burned-out vehicles in a remote southern Utah canyon Dec. 5.

In August, Thomas Cly, 22, and Vinton Bedoni, 31, were found guilty of first-degree murder and later were sentenced to life imprisonment. But U.S. District Judge J. Thomas Greene declared a mistrial in Atene's case when the jury could not reach a verdict after more than 46 hours of deliberation.

The original indictment also named Atene's brother, Marques Atene, 22. But charges against him were dropped after prosecutors said they did not have enough evidence to get a conviction.

Earlier Wednesday, a 12-member jury was impaneled from a pool of 83 potential jurors.

Assistant U.S. Attorney Stewart Walz said government witnesses would establish that Atene was at the scene of the Dec. 4 bonfire drinking party where the officers were shot. Five people who were at the bonfire, all of whom testified at the earlier trial, would be called as prosecution witnesses, he said.

They would testify that Atene kicked Roy Lee Stanley during a struggle, helped take him behind the truck where he was shot and later helped douse both officers with gasoline before they were set on fire, Walz said.

"He did enough to aid and abet those individuals . . . that he is just as guilty as Thomas Cly and Vinton Bedoni," Walz said.

Describing Atene as a "shy, timid 24-year-old Navajo youth," defense attorney Loren Weiss told the jury that it would have an "easy choice," because his client is innocent.

Weiss said defense witnesses would testify that Atene went home with a cold on Dec. 4 and was in bed by about 7 p.m., to be awakened at 5 the next morning to take part in a religious ceremony with family members.

Weiss also attacked the key prosecution witnesses, saying they had changed their statements several times and their testimony would be inconsistent with the physical evidence and each others' testimony.

"Such inconsistencies, such lies, are the basis upon which the government wants you to base your verdict," he said.

Some witnesses in the first trial had changed their statements several times before prosecutors threatened them with perjury.

Prosecutors contend the witnesses refused to admit being at the scene of the murder because they feared retribution from other tribal members, but defense attorneys said they only admitted being there in the first place under coercion by authorities.

Following the arguments, prosecutors called Leo Cadman of Kayenta, Ariz., who recounted how he found the vehicles with the officers' bodies while driving through Copper Canyon southeast of Lake Powell on a fishing trip.