It comes at a time when border agents are under increased scrutiny for the use of excessive force against migrants.
The trial for Agent Luis Fonseca is expected to be a short one. He's accused of choking unconscious a man believed to have crossed the border illegally. Fonseca has pleaded not guilty to the charges.
Federal prosecutors say that in 2011, Fonseca helped process a man detained near the border. In court documents, prosecutors allege Fonseca kneed him to the ground and then choked him. Afterward Fonseca allegedly told the man he was having a "Mexican heart attack."
A grand jury indicted Fonseca last year. Prosecutors say they have video of the attack.