The migrants were found in an abandoned truck on June 27, on an alley on the outskirts of San Antonio. The designated driver appeared in court on Wednesday at an arrest hearing.
Among the victims were a 13-year-old and a 14-year-old from Guatemala, and two 16-year-olds from Mexico. A total of 73 people were hidden in the hold.
Four different networks of human traffickers are suspected of being involved, according to the prosecutor.