An elite Border Patrol squad was pursuing a gang that preyed on drug smugglers when agent Brian Terry was shot and killed Tuesday night in a remote canyon south of Tucson, Homeland Security Secretary Janet Napolitano said Friday.

"They were seeking to apprehend what's called a 'rip crew,' which is a name given to a crew that is organized to seek to rip off people who are drug mules or traversing the border illegally," she said during a meeting with The Arizona Republic's editorial board. "That's why they were in that area."

Her comments were the first official confirmation that Terry and other members of the Border Patrol's specially trained tactical unit known as Bortac were pursuing bandits in a remote canyon west of Rio Rico the night the 40-year-old agent was killed in a gunbattle.

Four suspects, including one who was wounded in the shootout, are in custody. A fifth is at large.

Napolitano, a former Arizona governor, state attorney general and U.S. attorney, declined to provide details about the suspects or elaborate on the circumstances of Terry's death, citing the ongoing investigation. She was joined at the meeting by Alan Bersin, commissioner of U.S. Customs and Border Protection, the Homeland Security agency that includes the Border Patrol.

Napolitano toured parts of the border Friday and met with some of Terry's colleagues as part of a trip to Arizona that had been planned before Terry was killed.

But she reworked her schedule to meet with agents and praise the work they have done to increase security along the border, where the number of agents is at an all-time high.

"Here's the message that I gave to our Border Patrol agents down there, which is that the work they are doing is producing very, very strong results," she said.

"There is no doubt that the border, which I know very well, having dealt with it since '93, when I became U.S. attorney here, is a very different place than it was five years ago, six years ago."

Napolitano cited FBI crime statistics showing that violent crime in Arizona, Texas, California and New Mexico has declined sharply in recent years. She said agents have been, and still are, surging into the Border Patrol's Tucson Sector and that the National Guard will continue to maintain a border presence.

"We're seizing more currency, we're seizing more drugs, we're seizing more guns, and so those numbers are going up," she said. "And the illegal-immigrant apprehensions are down, which, again, is a measure that overall illegal immigration is down. So the numbers that need to be going up are going up and the numbers that need to be going down are going down, and substantially so."

The number of illegal-immigrant apprehensions in Arizona has plummeted from a high of 725,093 in fiscal 2000 to 219,318 in fiscal 2010, which ended on Sept. 30, Homeland Security statistics show.

Napolitano said she thinks the trend will continue.

The decrease in illegal-immigrant apprehensions likely is a combination of the poor economy and the increase in Border Patrol agents, the improved technology and border fencing, she said.

Congress has authorized funding for an additional 1,000 Border Patrol agents, who are being hired and trained. Napolitano said a "big swath" of the new agents will be assigned to the Tucson Sector.

Commissioner Bersin cited the increased staffing and technology on the border as a crucial factor in the four suspects in Terry's slaying being apprehended so quickly in such a remote, rugged area.

He concurred with Napolitano's characterization of the border as safer and more secure than it has been in years, but he cautioned that the stepped-up enforcement efforts and aggressive steps taken "to dismantle these entrenched smuggling and organized-crime groups" increase the danger for Border Patrol agents.

"They know that they stand between the American people and the Arizona community and this kind of danger," Bersin said. "That shooting, in fact, in some ways is the result of a challenge that is being made by law enforcement here to organized crime."

Terry's death this week has rekindled concerns about Mexico's bloody drug war spilling across the border into the United States.

But Napolitano said it would be wrong to conclude from Terry's death, as well as the killing of longtime Southern Arizona rancher Robert Krentz, that drug violence is on the rise or rampant along the border. Krentz's March slaying in Cochise County remains unsolved.

Funeral services

Funeral plans for Border Patrol agent Brian Terry have been set in his home state of Michigan:

• Viewing will be Monday and Tuesday at the John Molnar Funeral Home in Brownstown, Mich., about 25 miles southwest of downtown Detroit.

• There will be a church service Wednesday at the Greater Grace Temple in Detroit. After that, he will be taken to the nearby Michigan Memorial Cemetery where he will be buried next to his grandfather and uncle. There will be a full military service there, including a flyover, bagpipes and a 21-gun salute, said his older sister, Michelle Terry-Balogh.

- Brady McCombs