KENNEWICK, Wash.  >> When Agapita Montes-Rivera first watched the video of her son being gunned down by police in Washington state, she rushed to the TV set in a futile effort to help him.

The 60-year-old woman from tiny Parotita, Mexico, was more than 2,000 miles away and hadn’t seen her son in a decade.

"Truthfully, when I saw they were chasing him, and he puts his hands up, and they shoot him, I threw my hands at the television," Montes-Rivera said Tuesday. "Had I been there in person, I would have been the first to jump in so they wouldn’t have shot him."

Antonio Zambrano-Montes’ Feb. 10 death in the agricultural city of Pasco has sparked protests and calls for a federal investigation. Police killed the unarmed man who spoke little English after he allegedly threw rocks at officers.

In an interview with The Associated Press, Montes-Rivera said the three officers involved should go to prison.

"Police killed a person just for carrying a rock," she said in Spanish at a library in Kennewick, across the Columbia River from Pasco. Montes-Rivera was in Washington for the grim task of retrieving her son’s body and returning it to their village for burial.

"A lot of police who carry guns believe they can just kill anybody," she said. "It has happened too many times."

Pasco Police Capt. Ken Roske declined to respond directly to the woman’s comments. But he said the department has confidence in an investigation being conducted by a regional task force.

Authorities have said Zambrano-Montes was acting erratically the night of the shooting, and officers felt threatened. They said a stun gun failed to subdue the 35-year-old agricultural worker.

In a bystander’s video, five "pops" are audible, and Zambrano-Montes can be seen running away, pursued by three officers. As the officers draw closer, he stops, turns and faces them. Multiple "pops" are heard, and he falls to the ground near a busy intersection.

The Franklin County coroner has ordered an inquest into the death, and federal authorities are monitoring the task force probe.

Montes-Rivera, who has 16 children, said she was not aware of any erratic behavior in her son’s past.

"He was cheerful, a hard worker," said the mother, adding Zambrano-Montes came to the United States 10 years ago to find work and help out his family.

The family’s attorney, Benjamin Crump, has said Zambrano-Montes was in the country illegally and spoke little English. Crump also represented the family of Michael Brown, a black man killed by an officer in Ferguson, Missouri.

Court records show Zambrano-Montes was arrested last year for assault after throwing objects at Pasco police and trying to grab an officer’s pistol.

Montes-Rivera arrived in Pasco on Monday and had not yet had any contact with law enforcement. She said her husband was unable to make the trip and remained in Mexico.

The last time Montes-Rivera spoke with her son was Dec. 30, when she asked him to come home for a visit. He replied that he needed to make more money to do that.

The Mexican government is paying for Zambrano-Montes’ funeral home expenses and to transport the body back to Mexico, according to the Mexican counsel in Seattle. Mexico’s president earlier criticized the shooting.

Zambrano-Montes’ killing has sparked two weeks of protests in Pasco, which has a population of 68,000 and is more than 50 percent Hispanic.

Montes-Rivera says she is surprised by all the attention the death has received, and was overwhelmed when she visited a makeshift memorial to her son downtown.

The killing was the fourth by Pasco police in less than a year. Officers were exonerated after similar investigations in the first three cases. Critics in the latest case say the officers should have used less than lethal force to subdue Zambrano-Montes.

Authorities have said Zambrano-Montes was not armed with a gun or knife. Whether he had a rock in his hand when he was shot is still under investigation.

Two of the officers involved in his shooting were white, and the other Hispanic. All three opened fire, though the number of shots has not been disclosed.

Authorities have asked for patience as the investigation continues.