(Reuters) – The murder of a prominent Arizona rancher near the Mexican border is spurring charges that Washington is doing too little to stop Mexico’s raging drug war from spilling over into the United States.

U.S. | Mexico

Robert Krentz was shot last Saturday while working at his remote cattle ranch some 30 miles northeast of this city on the Arizona-Mexico border.

Investigators tracked the footprints of the suspected gunman about 20 miles south to the border with Mexico, prompting some authorities to blame smugglers or illegal immigrants for the killing.

“The ranchers have feared for their lives for a long time and they’ve told the people from Washington, but they don’t pay attention to us,” Michael Gomez, the mayor of Douglas, told Reuters.

“This continues to be a hot area for illegal crossings and they have to do something to stop it.”

Krentz, 58, was well liked and respected in southeastern Arizona, where his family’s ranch sprawled over 35,000 acres.

No arrests have been made and there is no clear motive or any named suspect, the Cochise County Sheriff’s Office said.

The killing comes amid ever-more brazen and brutal attacks by cartels in northern Mexico that are fighting for control of lucrative drug smuggling routes into the United States.

Last month, gunmen killed two Americans in Ciudad Juarez, south of El Paso, Texas, renewing fears in the United States that escalating violence may spill north over the border.

The U.S. Department of Homeland Security expressed “outrage” on Thursday at Krentz’s murder and posted a $25,000 reward for “information leading to the arrest and prosecution of the individual or individuals responsible.”

A day earlier, Bill Richardson, the Democratic governor of the neighboring state of New Mexico, ordered National Guard troops to patrol the border with Mexico to “ensure the safety of New Mexico citizens.”

Arizona Governor Jan Brewer and Senator John McCain, both Republicans, have urged President Barack Obama’s administration to send National Guard troops to boost efforts to secure the border with Mexico in the wake of the killing.

RESIDENTS FEARFUL

Obama has pledged support for Mexican President Felipe Calderon’s battle against the drug cartels. Calderon has deployed tens of thousands of troops to try to halt the violence that has killed more than 19,000 people since he took office in late 2006.

The area in southern Arizona where Krentz was murdered lies on the edge of a furiously trafficked corridor for both drug and human smugglers.

Last year Border Patrol agents made more than 241,000 arrests in the sector south of Tucson, Arizona, and seized more than 60 tonnes of marijuana.

In the wake of the murder, authorities in Douglas — a ranching town of 15,000 people over the border from Agua Prieta, Mexico — have added to calls on Washington to beef up security to protect isolated residents.

Gomez wrote to Homeland Security Secretary Janet Napolitano this week, urging her to send National Guard troops to tighten security along the border.

Without additional security, residents in Douglas said Krentz’s murder left many angry and fearful for their own safety.

“Rob was very highly respected and well thought of throughout the county, especially by his neighbors,” said Lynn Kartchner, the owner of a gun store that has done brisk business in the five days since the killing. “If they can get Rob, they can get anyone.” (Editing by John O’Callaghan)