PHOENIX — Officials from Arizona told U.S. senators on Tuesday that drug and immigrant smuggling violence along the U.S.-Mexico border has worsened over the last year.

The officials told senators at a hearing in Washington that the United States hasn’t seen the level of violence that Mexico is experiencing in its war against drug cartels. But criminals headed back to Mexico commit burglaries and home invasions along remote stretches of border, illegal immigrants are robbed and assaulted in their journey into the U.S. Drug and immigrant smugglers who have more limited trafficking routes also are stealing from each other and kidnapping rivals in Arizona, a busy hub for transporting illegal immigrants and marijuana into the United States.

“It is worse, and it is getting worse,” Cochise County Sheriff Larry Dever said of the violence.

The purpose of the Senate Homeland Security and Governmental Affairs Committee’s hearing was to see what federal, state and local officials can do to control the border, said Sen. Joe Lieberman, the independent from Connecticut who is the leader of committee.

Alan Bersin, commissioner of U.S. Customs and Border Protection, said the Obama administration came up with a plan more than a year ago to keep violence from spilling across the border.

Those efforts include trying to stop drug smugglers from sneaking guns and cash back into Mexico and having American prosecutors work with their Mexican counterparts to make sure smugglers are punished.

Under questioning from Lieberman, Bersin said 600 miles of border fencing and a $770 million network of cameras, ground sensors and radars known as the “virtual fence” weren’t stopping the flow of illegal immigrants into the country. “It doesn’t seal the border,” Bersin said.

Republican Sen. John McCain of Arizona, a member of the committee, advocated sending National Guard troops to the border to improve border security.

The latest major example of border violence cited at the hearing was the March 27 death of rancher Robert Krentz, who was shot on his ranch near Douglas, Ariz. Authorities provided a few details into the investigation of his death.

Dever, whose office is investigating the killing, said the rancher is believed to have been killed by an illegal immigrant who was headed back to Mexico and worked as a scout for drug smugglers. Scouts generally serve as mountaintop lookouts for drug smugglers, instructing the drivers for smuggling rings to pull over and hide when authorities are nearby.

Dennis Burke, U.S. attorney for Arizona, said federal authorities were culling its cases from the area of the killing to look for leads. Burke said it’s too early to link Krentz’s killing to a particular smuggling group.

After hearing a crushing amount of statistics on the massive volume of drugs seized and illegal immigrants arrested in Arizona, Dever said, “All of it added up to a big fat zero for Rob Krentz.”

Rancher Robert Krentz was killed March 27 on his 35,000-acre ranch near Douglas, Ariz. The killing of the third-generation rancher has become a flash point in the immigration debate as politicians cite the episode as further proof that the United States must do more to secure the violent U.S.-Mexico border. Photo by The Associated Press file

Michelle Roles