by Dennis Wagner - The Arizona Republic

The unsolved murder Saturday of a soft-spoken rancher in southern Arizona has become a new flashpoint in the debate over illegal immigration, with conservative media and politicians demanding increased border security.

Less than two days after authorities found the body of 58-year-old Robert Krentz, political bloggers and talk-show hosts began denouncing the federal government for a perceived failure to protect U.S. civilians from violent smugglers and other illegal border crossers.

After deputies and U.S. Border Patrol agents tracked footprints from the crime scene nearly 20 miles to the Mexican line, however, border policy critics declared that the killer was an illegal immigrant.

Two U.S. senators and a House member from New Mexico called for increased enforcement, according to published reports. And Tom Tancredo, an outspoken former Congressman from Colorado challenged Homeland Security Secretary Janet Napolitano to send in the National Guard.

U.S. Rep. Gabrielle Giffords, D-Tucson, offered condolences to the family in a news release and said the federal government "must respond appropriately" if the homicide was tied to smuggling. "All options should be on the table," she added, "including sending more Border Patrol agents to the area and deploying the National Guard."

More than half of all undocumented aliens arrested along the border last year were caught in the Tucson Sector, which covers most of southern Arizona. Omar Candelaria, a Border Patrol spokesman, said he is not aware of any U.S. citizen being murdered by illegal immigrants in that sector for more than a decade.

Capas, the sheriff's spokeswoman, said Krentz was working on a section of the ranch distant from his brother, Phil, and made a garbled radio contact about 10 a.m. Saturday, but only the words "illegal aliens" and "hurt" were audible. After Robert Krentz failed to meet his brother later in the day, family members launched a search and called the Sheriff's Office.

The body was discovered in an all-terrain vehicle shortly before midnight by an Arizona Department of Public Safety search helicopter. Capas said Krentz, who was married with three children, apparently managed to drive a short distance from the shooting scene before he became unconscious. His dog also had been critically wounded.

Capas said Phil Krentz had called Border Patrol agents to the Krentz Ranch one day before the homicide after witnessing illegal immigrant activity. She said the agents found more than 200 pounds of discarded marijuana and arrested eight undocumented immigrants in the area.

Richard Humphries, a former Arizona DPS officer, said he went to the crime scene on Sunday with Tancredo. He said it was an "ironic tragedy" that they had been planning a meeting that day with Phil Krentz and other area ranchers to discuss border security.

"This tragic incident has justifiably ignited a firestorm across southern Arizona," Humphries added.

While the political furor developed, Krentz' family and friends mourned the loss of a man they described as a calming influence, even when it came to the debate about border security.

Bas Aja, executive vice president of the Arizona Cattle Feeders Association, said Krentz and virtually every rancher south of Interstate 10 has expressed safety concerns because of crime related to smuggling and illegal immigration.

However, Aja and others said Krentz was always soft-spoken and thoughtful, willing to help immigrants who became lost or desperate after entering the country unlawfully. "Rob Krentz, first of all, was a very gentle soul," Aja said. "He was a caretaker for his family, for the land and for the animals he raised."

Although southern Arizona ranchers could not recall any civilians being killed by illegal immigrants, many said they are wary now while riding the range.

"Our cowboys are armed with .45s when they go out on the ranch everyday because they're scared to death," said Bill McGibbon, a friend of Krentz who runs cattle in the Santa Rita Mountains.

"We're always very careful," added Dan Bell, a Nogales rancher. "But this whole thing has got me to thinking."

For more than a century, Krentz and his family worked a spread that covers about 35,000 acres stretching into Chiricahua Mountains northeast of Douglas. He is a former president of the Cochise County Cattle Growers Association. His family was inducted into the Arizona Farming and Ranching Hall of Fame in 2008.

Aja said the state Cattleman's Association had collected $10,000 as of Monday to post a reward for information about the killer.

No announcement has been made regarding memorial services.