Whether two Border Patrol agents went from protectors to perpetrators, as prosecutors say, or were simply following orders will be determined by the jury in a trial that is expected to last a couple of weeks.

Dario Castillo and Ramon Zuniga are on trial in federal court in Tucson charged with violating the civil rights of four men caught smuggling on Nov. 12, 2008, in a remote stretch of the border on the Tohono O'odham Nation.

Four agents, including the defendants, encountered a group of 12 smugglers at about 10:30 p.m. three miles from the border.

Eight of them fled but four were caught. Instead of arresting them, an indictment says, the two agents forced some of the smugglers to eat marijuana and to remove their outer clothing, which prosecutors said included their shoes, socks and jackets.

The agents set fire to the men's belongings and told them to flee on a night when temperatures were about 40 degrees, the indictment states.

"'Run, get out of here,' these are the words of Border Patrol agents to four men caught breaking the law," Assistant U.S. Attorney Karen Rolley told the jury in her opening statement Tuesday.

According to prosecutors, the men fled and dug a hole in a wash and covered themselves with branches and plastic until the following day, when they turned themselves in to tribal police and said they had been robbed by bandits.

Once they were turned over to the Border Patrol, the smugglers said it had been Border Patrol agents.

Castillo and Zuniga were indicted in August 2011. Castillo is also being charged with tampering with a witness for allegedly asking one of the agents to lie about what he had seen.

The two are on administrative leave from the agency.

Attorney Sean Chapman, who represents Zuniga, said the account of what happened is fiction created by the two other Border Patrol agents at the scene.

The defense argues agent Jose Grajeda, who had seniority over the two agents, was calling the shots that night. He will be cross-examined by the defense today

Chapman and Michael Bloom, who represents Castillo, challenge the credibility of the prosecutor's witnesses.

"They were high as a kite," Bloom told the jury about the four smugglers, and they initially lied about what had happened to protect themselves.

The jury needs to ask themselves, "What does it tell me about these people?" Bloom said.

The defense also challenges the initial report Grajeda filed saying he and agent Aaron Veckey found 21 bundles of marijuana abandoned, but didn't find anyone. He made no mention of the smugglers or what allegedly happened.

Rolley said prosecutors will present evidence from emails and calls between agents that prove they conspired and violated the civil rights of the four men.

On several occasions she told the jury the testimony from the other two agents and the four smugglers will not be completely consistent, but asked them to focus on the evidence.

Regarding the charge of forcing the drug smugglers to eat marijuana, Chapman said Zuniga asked if they liked marijuana and when they responded yes, he told them they should eat it and allegedly they grabbed it and put it in their mouths.

"Was it wrong? Yes. Should he get fired for it? Maybe. Is that a civil rights violation? That's for you to decide," Chapman told the jury.

Contact reporter Perla Trevizo at ptrevizo@azstarnet.com or at 573-4213. On Twitter: @Perla_Trevizo