Prosecutors said there was insufficient evidence to charge a Border Patrol agent in connection with the slaying of 15-year-old Sergio Hernandez-Guereca.
Hernandez-Guereca was killed when an agent fired into a crowd on the Mexican side of the border who was allegedly pelting him with rocks as he detained an undocumented immigrant along the Rio Grande River near Juarez.
The Justice Department said in a statement civil rights violations did not apply because the teenager was not inside the United States when he was killed. The investigation also concluded the agent acted within Border Patrol regulations.
"This review took into account evidence indicating that the agent's actions constituted a reasonable use of force or would constitute an act of self defense in response to the threat created by a group of smugglers hurling rocks at the agent and his detainee," the statement said.
Mexico reacted angrily to the decision after it was announced Friday. The Los Angeles Times said the Foreign Ministry issued a statement rejecting the decision and vowed to assist the youth's family in a civil case filed in a U.S. court.