An Arizona man who has waged a 10-year campaign to stop a flood of illegal immigrants from crossing his property is being sued by 16 Mexican nationals who accuse him of conspiring to violate their civil rights when he stopped them at gunpoint on his ranch on the U.S.-Mexico border.

Roger Barnett, 64, began rounding up illegal immigrants in 1998 and turning them over to the U.S. Border Patrol, he said, after they destroyed his property, killed his calves and broke into his home.

His Cross Rail Ranch near Douglas, Ariz., is known by federal and county law enforcement authorities as "the avenue of choice" for immigrants seeking to enter the United States illegally.

Trial continues Monday in the federal lawsuit, which seeks $32 million in actual and punitive damages for civil rights violations, the infliction of emotional distress and other crimes. Also named are Mr. Barnett's wife, Barbara, his brother, Donald, and Larry Dever, sheriff in Cochise County, Ariz., where the Barnetts live. The civil trial is expected to continue until Friday.

The lawsuit is based on a March 7, 2004, incident in a dry wash on the 22,000-acre ranch, when he approached a group of illegal immigrants while carrying a gun and accompanied by a large dog.

Attorneys for the immigrants - five women and 11 men who were trying to cross illegally into the United States - have accused Mr. Barnett of holding the group captive at gunpoint, threatening to turn his dog loose on them and saying he would shoot anyone who tried to escape.

The immigrants are represented at trial by the Mexican American Legal Defense and Educational Fund (MALDEF), which also charged that Sheriff Dever did nothing to prevent Mr. Barnett from holding their clients at "gunpoint, yelling obscenities at them and kicking one of the women."

In the lawsuit, MALDEF said Mr. Barnett approached the group as the immigrants moved through his property, and that he was carrying a pistol and threatening them in English and Spanish. At one point, it said, Mr. Barnett's dog barked at several of the women and he yelled at them in Spanish, "My dog is hungry and he's hungry for buttocks."

The lawsuit said he then called his wife and two Border Patrol agents arrived at the site. It also said Mr. Barnett acknowledged that he had turned over 12,000 illegal immigrants to the Border Patrol since 1998.

In March, U.S. District Judge John Roll rejected a motion by Mr. Barnett to have the charges dropped, ruling there was sufficient evidence to allow the matter to be presented to a jury. Mr. Barnett's attorney, David Hardy, had argued that illegal immigrants did not have the same rights as U.S. citizens.

Mr. Barnett told The Washington Times in a 2002 interview that he began rounding up illegal immigrants after they started to vandalize his property, northeast of Douglas along Arizona Highway 80. He said the immigrants tore up water pumps, killed calves, destroyed fences and gates, stole trucks and broke into his home.

Some of his cattle died from ingesting the plastic bottles left behind by the immigrants, he said, adding that he installed a faucet on an 8,000-gallon water tank so the immigrants would stop damaging the tank to get water.

Mr. Barnett said some of the ranch´s established immigrant trails were littered with trash 10 inches deep, including human waste, used toilet paper, soiled diapers, cigarette packs, clothes, backpacks, empty 1-gallon water bottles, chewing-gum wrappers and aluminum foil - which supposedly is used to pack the drugs the immigrant smugglers give their "clients" to keep them running.

He said he carried a pistol during his searches for the immigrants and had a rifle in his truck "for protection" against immigrant and drug smugglers, who often are armed.

A former Cochise County sheriff´s deputy who later was successful in the towing and propane business, Mr. Barnett spent $30,000 on electronic sensors, which he has hidden along established trails on his ranch. He searches the ranch for illegal immigrants in a pickup truck, dressed in a green shirt and camouflage hat, with his handgun and rifle, high-powered binoculars and a walkie-talkie.

His sprawling ranch became an illegal-immigration highway when the Border Patrol diverted its attention to several border towns in an effort to take control of the established ports of entry. That effort moved the illegal immigrants to the remote areas of the border, including the Cross Rail Ranch.

"This is my land. I´m the victim here," Mr. Barnett said. "When someone´s home and loved ones are in jeopardy and the government seemingly can´t do anything about it, I feel justified in taking matters into my own hands. And I always watch my back."