ED ROCK, Ariz., Oct. 22 — The police are investigating whether armed vigilantes, self-appointed guardians of the border with Mexico, fatally shot at least two illegal immigrants in the desert last week.
A 32-year-old man who was part of a group of a dozen migrants waiting to be picked up by smugglers at a pond just west of here last Wednesday told investigators that he escaped through the brush after two men wearing camouflage fatigues descended on the group, firing an automatic rifle and a pistol.
Police officers found two bodies riddled with bullets and no sign of the remaining nine migrants. It is not known whether they escaped or were loaded into vehicles and taken away, either dead or alive.
Mike Minter, a spokesman for the Pinal County Sheriff's Department, said detectives were looking into several possibilities, including a suggestion that the shootings were a result of a dispute between rival coyotes, as the smugglers who guide migrants across the border are called.
Mr. Minter said the nine missing people "may have been taken from one coyote group by another coyote group." Conversely, he said, the possibility that vigilantes were involved "hasn't been ruled out."
Migrants-rights advocates in Tucson, about 30 miles southeast of here, say the killings are part of a vigilante terror campaign intended to stop the flow of immigrants from Mexico.
The advocates discounted the notion that rival coyotes, who usually blend in with their charges so as to avoid detection, were responsible for the killings.
"Never have I seen a coyote or a smuggler wear camo or military dress," said John M. Fife, pastor of Southside Presbyterian Church in Tucson and a former member of the Sanctuary movement, which helped political refugees, primarily from Central America, gain asylum in the United States in the 1980's.
At a news conference on Monday, Isabel Garcia, 49, a public defender in Pima County and co-chairwoman of the Human Rights Coalition/Indigenous Alliance Without Borders, said the killings "crystalize the increasingly hostile and violent atmosphere created by failed U.S. border policies."
Members of the self-professed border guardian groups denied any connection to last week's deaths. Glenn Spencer, founder of American Border Patrol, based in Sierra Vista, 19 miles north of the Mexican border, said his associates carried weapons during their patrols only for protection against mountain lions.
But Mr. Spencer, 65, acknowledged that his goal was to repatriate all illegal immigrants, even ones who have been in the country for years.
"They're able to outsmart us all the time," Mr. Spencer said of the migrants. "I'm not interested in enforcing the law. It's about telling the American people what's going on at the border."
Roger Barnett, who lives on a 22,000-acre ranch two miles north of the border, near Douglas, and who heads Ranch Rescue, the most visible of the citizens' patrol groups, said coyotes were responsible for the killings last week. The border was "out of control," Mr. Barnett said.
"The government has left us alone out here — they forgot about us," Mr. Barnett said from his tow-truck shop in Sierra Vista. "They got one hell of a problem here with these invasions from Mexico."
Mr. Barnett, who has allied himself with Mr. Spencer's group, said he and his brother, Donald, had detained at least 8,000 illegal immigrants over the past four and a half years and turned them over to the United States Border Patrol. He said that the migrants, who are made to sit on the ground, sometimes "get mouthy with us" and that he was forced to become physically aggressive to control them.
"If you go out there and you're not armed, you're a fool," said Mr. Barnett, who carries a 9-millimeter pistol. "Who's going to protect you out there?"
A brochure distributed by one of the citizens' patrols urges volunteers around the country to "come and stay at the ranches and help keep trespassers from destroying private property." Next to a headline that reads "Fun in the Sun," the invitation says that volunteers "may be deputized if necessary."
Members of Ranch Rescue said that, clad in camouflage and armed with semiautomatic rifles, they seized about 280 pounds of marijuana a week ago from smugglers crossing the border near Lochiel, 65 miles south of Tucson.
Sheriff Marco Antonio Estrada of Santa Cruz County, where Lochiel is, said Ranch Rescue teams did not have the training to intercept drug traffickers and might lead such smugglers to believe that trafficking was easier, if they were not up against federal officers or local deputies.
"I have concerns that they're not really welcome, or really not needed," Sheriff Estrada said of the citizens' patrols. "They are not helping law enforcement, definitely not."
The known survivor of last week's shootings is being cared for by Mexican consular officials in Tucson, who declined to make him available for comment because he is a material witness in the case.
Carlos Flores Vizcarra, the consul, said so-called vigilantes who police the border "put out a message of fear and intimidation" that prevents a resolution of larger questions of immigration.
Farther north, the Maricopa County Sheriff's Department is investigating the killing of eight men, at least six of them Mexican citizens, whose bodies were found from June to September in the desert west of Phoenix. The men were gagged and handcuffed or bound with duct tape and elastic bands. Seven had been shot in the back of the head; the eighth was stabbed.
Investigators were looking into the possibility that smugglers had killed them for their money, or that they were involved in drug trafficking. Lt. J. J. Tuttle, a sheriff's department spokesman, said hate groups or vigilantes might also be to blame.
A broad expanse of desert in southern Arizona has been the nation's busiest region for illegal border crossings for the past five years, with more than 333,000 arrests by the Border Patrol in the fiscal year ending Sept. 30. With 261 miles of border, the area has become even more active since the Sept. 11 terrorist attacks, which brought increased enforcement of restrictions on crossings in California and Texas.
The harsh conditions of Arizona's deserts led to the deaths of at least 134 migrants, primarily from dehydration and exposure, in the 2002 fiscal year ended Sept. 30, up from 11 in 1998. The number is more than double that of the second-most-perilous district, in eastern California, where 63 people died in the last fiscal year.
At the scene of the shootings here, yellow police tape fluttered in the breeze tonight by the algae-covered pond. On the ground, four sticks were arranged in the form of a cross; while underneath them an X had been burned into the dirt. David Cook, assistant manager of the Red Rock Custom Feeding Company, about a mile west of the pond, recalled his conversation with the survivor of the shootings, who had gone there for help in what Mr. Cook called a "panicked" state.
"He kept telling me, `They were soldiers, they were soldiers', " Mr. Cook said. "I told him that soldiers don't kill people up here."