By Elliot Spagat
SAN DIEGO — A 17-year-old pleaded guilty Friday to killing a Border Patrol agent who was shot eight times while chasing suspected illegal immigrants in the mountains east of San Diego.
Christian Daniel Castro Alvarez said he lured Agent Robert Rosas out of his car last July 23 and struggled over his gun during a robbery attempt, the U.S. attorney's office said.
The attack sparked a massive search on both sides of the border in rugged terrain strewn with white boulders that is popular with illegal immigrants and marijuana smugglers.
Castro Alvarez was charged as an adult after surrendering Aug. 14 at the San Ysidro border crossing connecting San Diego and Tijuana, Mexico.
"Today's guilty plea makes it clear that those who harm our brave men and women in uniform will be swiftly brought to justice and punished," Homeland Security Secretary Janet Napolitano said.
Rosas, 30, was the first Border Patrol agent killed by gunfire since 1998, according to The Officer Down Memorial Page, a Web site that tracks deaths of law enforcement officers.
Castro Alvarez appeared before U.S. Magistrate Judge James Lorenz to enter his plea to murdering a federal officer in perpetration of robbery.
Rosas was patrolling alone and volunteered to pursue a group of suspected illegal immigrants spotted by another agent using a night-vision scope mounted on the back of a pickup truck, authorities said.
Rosas left his car with the ignition on while pursuing three people on the cool, dark night. He was shot four times in the head, once in the neck and three times in the torso. His Border Patrol-issued gun was missing.
Authorities said Castro Alvarez acted with others but did not immediately say how many. The suspects are believed to have fled back to Mexico through a small crevice under a border fence made of corrugated metal.
"Our work on this case is not yet done," U.S. Attorney Karen Hewitt said.
Napolitano thanked the Mexican government for cooperating in the case.
Castro Alvarez could face a maximum of life in prison when he is sentenced Feb. 19. His attorney, Ezekiel Cortez, did not immediately respond to a phone message.
Since the attack, the Border Patrol has expanded its presence in the area and been assigning agents to work in pairs instead of alone.
The FBI and Border Patrol offered rewards totaling $350,000 for information leading to the arrest and conviction of those responsible. The FBI offered an additional $10,000 for help finding Rosas' .40-caliber gun.
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The FBI has not yet recovered the weapon, spokesman Darrell Foxworth said.