NEAR PORTAL - Neighbor ranchers of the slain Robert Krentz say they had been warning U.S. officials for years that somebody would be killed if they didn't gain control of this dangerous smuggling corridor where armed burglaries have become a daily occurrence.

Now, they're demanding immediate action.

Krentz, a longtime rancher, was shot and killed Saturday in Cochise County, by a likely southbound smuggler, who authorities believe escaped into Mexico.

"The Mexican outlaws have total control, and it's going to get worse," said Ed Ashurst, whose 53,000-acre ranch is just east of the Krentz ranch. "There is going to be more bloodshed."

On Monday, in reaction to the killing, Gov. Jan Brewer reiterated a March 2009 request to send 250 additional National Guard soldiers to Arizona's border.

Rancher Dean Nelson said the National Guard should have already been called. "If the government doesn't call out the Guard, they don't care about us," Nelson said.

But Ashurst said the National Guard won't improve safety unless its personnel are given the green light to shoot at smugglers.

"They are going to have to kill some of those outlaws," Ashurst said. "I am going to protect myself and I will use deadly force. . . . I have a gun, and if an illegal alien ever gets in my house, he's dead."

The desire for a more aggressive stance at the border is shared by others in the area.

"Dig a ditch 20-feet deep and when they cross it, that's where they stay," said Hal Mortensen, a retired rancher and lifelong Cochise County resident who had known Krentz for 40 years.

Ranchers in the unincorporated community of Apache, about 25 miles northeast of Douglas, say they'll now be more vigilant when they encounter illegal immigrants.

Ashurst, Nelson and Mortensen described Krentz as a good man who didn't have enemies.

Cochise County Sheriff Larry Dever called the incident a "senseless shooting." He said there is no evidence to suggest there was any confrontation.

"There is absolutely no reason this had to happen other than the bad intentions of one sick, sorry individual that we hope to be able to catch up to very quickly," Dever said.

The sheriff said he's worried angry ranchers may take matters into their own hands with smugglers.

"I'm angry as well, but the law is the law, and we have to act within certain constraints, and we'll encourage everybody else to do the same," Dever said.

Krentz, who was out checking water lines and fencing on his family's 35,000-acre ranch, had weapons with him on the ATV he was riding, but he did not use them, Dever said.

Investigators have determined the shooting was carried out by one person, but they don't know anything about the person.

They believe it was an illegal immigrant because Krentz was heard telling his brother on two-way radio "illegal alien" and because the area is a known smuggling corridor.

They have no motive.

Dever said Krentz was frustrated and fed up with the illegal activity like many ranchers in the area. But he said he was compassionate and regularly helped illegal immigrants in distress.

"There is no reason to believe anything else other than what happened that day with Rob," said Dever.

Krentz was found about 1,000 feet from where they believe the shooting occurred, dead on his ATV. The ATV still had its lights on and the engine running, Dever said. There were spin-out marks in the dirt, leading investigators to believe that he was trying to get away, Dever said.

Investigators believe the shooter was headed toward the border when Krentz encountered him. Law enforcement tracked a single set of footprints - believed to be the shooter's - for 20 miles to the U.S.-Mexico border. They also contacted Mexican authorities, but so far there is no information about the killer.

Dever said it will be very difficult to find the shooter and would likely require that the shooter talk about the incident with somebody.

While investigators don't have a motive yet, retaliation has been raised as a possibility, Dever said.

The day before the shooting, the victim's brother, Phil Krentz, reported drug smuggling on the ranch to the Border Patrol.

Agents found 290 pounds of marijuana on the ranch and followed tracks to where they found and arrested eight illegal immigrants, said Robert Boatright, deputy chief of the Border Patrol's Tucson Sector. None were prosecuted because of a lack of evidence. They were all in custody when the shooting occurred, he said.

Krentz regularly called the Border Patrol to let it know about illegal activity on the ranch, the agency said.

Dever also said there was another incident within 24 hours of the shooting that could be connected involving a gun, but he would not elaborate.

The area where the shooting occurred is a well-known drug- and people-smuggling corridor, Boatright said. In the summer of 2009, after seeing a spike in activity in the area, the agency opened a base staffed around the clock with 20 agents.

Dever said his deputies have responded to several calls from residents in the area about burglaries, property damage and even a few home invasions. Recently, the county had assigned all of the deputies working overtime hours under a Department of Homeland Security grant program to the area.

"There has been a prevailing sense for sometime in the community that something like this was going to happen," Dever said.

Krentz was a member of the board of directors of the Malpai Borderlands Group, an organization of conservation-minded ranchers.

Krentz's family had been ranching their property since 1907, and in 2008 the Krentz Ranch was inducted into the Arizona Farming and Ranching Hall of Fame.

"His impact on ranching in Southern Arizona can't be overstated nor can his contributions to Cochise County," said former state Sen. Jonathan Paton of Tucson. "Mr. Krentz's compassion and spirit will be remembered by many as we try to understand this senseless tragedy."

There is a community meeting planned for 6 p.m. Wednesday in the schoolhouse in Apache to discuss safety issues.

Star reporters Brian J. Pedersen and Tim Steller contributed to this report. Contact reporter Brady McCombs at 573-4213 or