Authorities intended to track the guns into Mexico. Two rifles found at the scene of Terry's shooting were bought by a member of the gun-smuggling ring being investigated. Critics of the operation say any shooting along the border now will raise the specter that those illegal weapons are still being used.
Twenty-six Border Patrol agents have died in the line of duty since 2002.
Associated Press writers Brian Skoloff in Phoenix, Susan Montoya Bryan in Albuquerque, N.M., and Olga R. Rodriguez in Mexico City contributed to this report.