The trial in U.S. District Court in Tucson, Arizona, comes amid President Donald Trump's crackdown on illegal immigration and his promise to build a wall along the 2,000-mile (3,200-kilometer) U.S.-Mexico border.
Lonnie Swartz has pleaded not guilty to second-degree murder in the killing of 16-year-old Jose Antonio Elena Rodriguez. The teenager was on a street in Nogales, in the Mexican state of Sonora, just across the border from Nogales, Arizona.
An autopsy showed the unarmed teen was shot 10 times, mostly from behind. Collins asked prospective jurors whether they knew possible witnesses, including more than a dozen Border Patrol employees, FBI officials and several residents of Nogales, Sonora.
Lee Gelernt, a New York-based lawyer with the American Civil Liberties Union, said he believes Swartz is the first border agent to be prosecuted by the U.S. Justice Department in a fatal shooting across the border.
Gelernt is handling a civil lawsuit for the teen's mother, who is seeking monetary damages against Swartz. "This historically important trial is coming at a time when all eyes are on the border," he said.
Prosecutors say Swartz opened fire at about 11:30 p.m. on Oct. 10, 2012, through the metal poles of a 20-foot (6-meter) fence that sits on a 25-foot (about 7.6-meter) embankment above Mexico's Calle Internacional, a street lined with homes and small businesses.
About 20,000 people live on the Arizona side and about 300,000 live on the Mexico side, but the two communities linked by family members, trade and culture have long been referred to locally as "Ambos Nogales" — "Both Nogales" in Spanish.
Swartz's lawyers have said just before he was shot, Elena Rodriguez threw rocks in an attempt to create a distraction for drug smugglers and that the officer was justified in using lethal force. They have requested that jurors visit the site at night to experience the area after dark.
Witnesses from the Mexico side of the border said they did not see the teen throw rocks and his relatives have denied he was helping drug smugglers, saying he was walking home after playing basketball.
The U.S. Attorney's office has said it won't dispute that the boy was throwing rocks, but it's unknown if he had any link to drug smugglers. They argue an unreasonable amount of force was used. Swartz pleaded not guilty after being indicted by a federal grand jury in 2015 and is currently on administrative leave and free on his own recognizance. The Border Patrol has not said if he is continuing to receive his salary.
Defense attorney Sean Chapman has declined to comment while the trial is ongoing. A spokesman for the agents' union, the National Border Patrol Council, did not respond to multiple requests for comment.
The case is expected to last more than a month and activists who oppose U.S. border policies have said they will rally outside the courthouse. "For so long, prosecutors have been reluctant to charge Border Patrol agents with violent crimes," said John Fife, a retired Presbyterian minister who was active in the sanctuary movement that sheltered citizens of Central American countries who came to the U.S. in the 1980s fleeing civil war. "Now we will see if they can be held accountable."