Video taken by a witness shows Zambrano-Montes running from officers. As the officers draw closer, he stops, turns and faced them. Multiple “pops” are heard, and then he falls to the ground.Lattin said officers fired stun guns at least twice but failed to stop Zambrano-Montes before firing their weapons.

Zambrano-Montes was shot to death around 5 p.m. at a busy intersection in Pasco. His death has sparked two weeks of protests in this majority-Hispanic agricultural city along the Columbia River in the southeastern part of the state.

Authorities say the Mexican immigrant was throwing rocks at passing vehicles and later at responding officers. The Franklin County coroner has ordered an inquest into the death.

Federal authorities have said they are monitoring the local investigation. Lattin said it will be thorough and fair.

“We’re not here to cover up for anybody,” he told reporters.

Lattin said a rock was found next to Zambrano-Montes’ body, but no gun or knife.

Critics of the shooting continued to call for a federal investigation. The American Civil Liberties Union has also asked the federal government to intervene.

Felix Vargas, a Hispanic leader from Pasco, said he met with a federal official last weekend and had a meeting scheduled for later Wednesday with U.S. Attorney Michael Ormsby of Spokane, Wash., to discuss the case. That meeting was closed to reporters, he said.

The FBI has said it is monitoring the local investigation.

Charles Herrmann, an attorney representing Zambrano-Montes’ estranged wife and two teenage daughters, said it is difficult for neighboring police officers to investigate their colleagues.

“I do not think these authorities can conduct a truly impartial investigation of their brother officers,” Herrmann said. He also doubted that Franklin County Prosecutor Shawn Sant was inclined to bring charges against the officers involved.

“The Zambranos are going to have their day in court,” Herrmann predicted.

He said the widow, Teresa De Jesus Meraz-Ruiz, who lives in California, was “devastated” by the shooting. The couple has reportedly been estranged since 2006.

Meanwhile, Lattin said the special investigations unit, made up off officers from four neighboring cities, was awaiting final toxicology and other lab reports before sending its final report to the prosecutor. He predicted that would take several more weeks.

Sant said it would take about 60 days after the report is finished to begin the coroner’s inquest. The contents of the report will be released during the inquest, but not before, he said.

The family also commissioned its own autopsy.

Lattin said the three officers would not be interviewed until all the other preliminary work of the investigation is completed.

Officers continue to seek details of Zambrano-Montes’ whereabouts in the two weeks before the shooting. His home had recently burned and he had stayed for a time in a homeless shelter, but no one has yet been able to account for his actions in the two weeks prior to his death, Lattin said.

Officers want to know if he was suffering from mental health issues, drug use or an injury, Lattin said.

Lattin said this would be the last of his weekly briefings to the news media because officials did not want to contaminate future jury pools.

The killing was the fourth by police in less than a year for fast-growing Pasco, a city of 68,000 where more than half the residents are Hispanic but few are members of the police force or the power structure.

Officers were exonerated after similar investigations in the first three cases. Critics of the latest case say the officers should have used less than lethal force to capture Zambrano-Montes.

Police said officers felt threatened. Zambrano-Montes was arrested last year for assault after throwing objects at Pasco officers and trying to grab an officer’s pistol, court records show.