The case against an FBI agent charged with lying about firing two shots at Oregon standoff spokesman Robert "LaVoy" Finicum most likely will turn on expert testimony about the validity of the Deschutes County Sheriff's Office investigation, a defense lawyer said Thursday.

No one reported that they saw or heard agent W. Joseph Astarita fire and no direct evidence exists linking any bullet or shell casing to Astarita's rifle, one of his lawyers said.

Prosecutors countered that the investigation continues and revealed for the first time that not only are shell casings from Astarita's alleged shots missing, but so are shell casings from some of the Oregon State Police shots fired at the Jan. 26, 2016, roadblock.

"Eight shots were fired. Six shell casings in roadway are all gone," said Assistant U.S. Attorney Pam Holsinger, chief of the Criminal Division in the Oregon U.S. Attorney's Office. She didn't elaborate.

State troopers fired six of the eight shots, with the other two eventually linked to Astarita, investigators and prosecutors said.

The Oregonian/OregonLive previously reported two bullet casings that might have proven an FBI agent shot at Finicum apparently disappeared from the scene.

The shooting came as state police and FBI agents stopped key figures of the armed occupation of the Malheur National Wildlife Refuge as they left the bird sanctuary for a community meeting in John Day.

Astarita, who continues to work for the FBI in an administrative role, was indicted in late June and has pleaded not guilty to three counts of making a false statement and two counts of obstruction of justice.

He is accused of concealing from Oregon investigators that he fired his rifle and lying to three supervisory FBI agents about his shots.

Lawyers from both sides of the case met for a brief status conference in federal court in Portland. The case has been designated as complex and a trial date was rescheduled for Feb. 27.

David Angeli, one of four criminal defense lawyers retained by Astarita, signaled that his client likely will challenge the forensic analysis and "modeling'' done by the Deschutes County Sheriff's Office, which was tasked with investigating the Finicum shooting.

The defense may question whether the sheriff's investigators were qualified to conduct the work and if their conclusions are valid, Angeli said.

The investigators established that a bullet entered Finicum's truck through the roof as he was stepping out at the roadblock on U.S. 395 in Harney County and concluded Astarita fired it. Another bullet from Astarita apparently went wild and missed the truck altogether, the investigation showed.

The detectives also found that state troopers fired three shots into Finicum's truck as it was barreling toward the roadblock and three more shots that struck Finicum, killing him after he had emerged from his truck and reached inside his jacket. He was carrying a loaded 9mm pistol in a pocket, authorities said.

As he crashed in a snowbank at the roadblock, Finicum nearly struck another FBI agent with his truck, investigators said.

The troopers reported their shots, yet it's unclear why four casings from their shots weren't found at the scene.

The indictment says Astarita, who served as a member of the elite FBI Hostage Rescue Team, "falsely stated he had not fired his weapon during the attempted arrest of Robert LaVoy Finicum, when he knew then and there that he had fired his weapon.''

Assistant U.S. Attorney Paul Maloney also noted that discussions are underway with the lawyer representing Ryan Bundy, one of the occupation leaders who was in the back seat of Finicum's truck.

Investigators want to recover a "metallic object" in Bundy's shoulder, Maloney said. They want to analyze it as potential evidence in the case.

So far, the government has provided Astarita's lawyers with two volumes of discovery evidence, representing more than 8,000 pages, as well as audiotapes and video. Two more volumes of evidence will be shared, including all the officer-involved shooting reports and data from the examination of five computers and multiple cellphones, Holsinger said.

The government expects to call experts as witnesses to testify about the sheriff's office analysis of the ballistic evidence and video of the shooting.

Based on the evidence he's reviewed so far, Angeli said there's no witness identified who reported seeing or hearing Astarita fire a shot, and Astarita didn't tell anybody he fired a shot.

In March 2016, the Deschutes County Sheriff's Office and FBI announced that an FBI agent was suspected of firing twice at Finicum and may have gotten help from four other FBI agents in covering up afterward. No other agent has been charged in the case.

Holsinger noted that the FBI agents under investigation had a union lawyer at the time the criminal inquiry began.

-- Maxine Bernstein

mbernstein@oregonian.com

503-221-8212

@maxoregonian