The group he was with – at least twenty migrants and two smugglers, known as "coyotes" – reportedly left him there.
Witnesses told investigators the agent shot the man while he was down on the ground. The agent's lawyer denied the claim.
The U.S. State Department has ordered its consular employees to use only armored cars when driving in the Mexican state of Sonora.
At 27 percent, Yuma County's unemployment rate is the second worst in the country, just behind neighboring Imperial County, California.
A federal agent on horse patrol in a remote area near the Nogales border Tuesday morning, shot a Mexican national in the abdomen. The Border Patrol has given no information saying that the case is under investigation by the FBI.
Citing concerns of violence in Mexico, the state of Arizona has ordered its fruit and vegetable inspectors not to cross the border to check the goods coming into the state. The produce industry says the mandate leaves them unprepared to deal with the resulting backup.