A prominent Arizona rancher likely was killed by an illegal immigrant, but there's no evidence to suggest there was any confrontation that led to the shooting, sheriff's investigators said.

Robert Krentz, 58, was a third generation rancher who was inducted into the Arizona Farming and Ranching Hall of Fame one year ago. He has served as president of the Cochise-Graham Cattlegrowers Association.

"We know this," Cochise County Sheriff Larry Dever said at a news briefing. "Robert was shot. His dog was shot. He was in an all-terrain vehicle and he never got out of the vehicle. "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.

Krentz was found shot to death just before midnight Saturday on his property about 35 miles northeast of Douglas. Dever told the Arizona Daily Star retaliation may have a role to play in the death. The newspaper said the victim's brother told the Border Patrol there had been drug-smuggling activity on the ranch.

The newspaper said agents discovered 290 pounds of marijuana on the ranch. Eight illegal immigrants were arrested in connection with the alleged activity, the newspaper said.

Sheriff Dever said it appears Krentz tried to drive away after he was shot but lost consciousness about a thousand feet from the scene. Investigators said they found foot tracks leading away from the area. They said they followed them for about 20 miles to the Mexican border.

“The cold-blooded killing of an Arizona rancher is a sad and sobering reminder of the threats to public safety that exist in our border communities,” said U.S. Rep. Gabrielle Giffords of Arizona’s 8th Congressional District.

"If, as suspected, this tragedy was connected to smugglers or drug cartels, the federal government must respond appropriately," Giffords said. "All options should be on the table, including sending more Border Patrol agents to the area and deploying the National Guard."

Minutemen member Chris Simcox said news of the death was unsettling but not a surprise.

"There's a war going on in Mexico and its spilling across our borders," Simcox said. "He's been working with Border Patrol for years, begging and pleading for help with his property being vandalized and his home being robbed," Simcox said.

"He's always been a humanitarian," Simcox said. "He always gives water and food to the people he finds in distress which seems to be the case last night and he called his wife and said he was giving some water to illegals and said to call Border Patrol."

Source: Arizona Daily Star