Experts have been warning for months that the administration's policies would only increase risks for migrants.
School officials learned of the incident after video of it went viral online.
The U.S. Army sergeant could face life in prison if convicted of misbehavior before the enemy.
Earlier this year, Bergdahl was charged with desertion and misbehavior before the enemy.
Investigations by the Bexar County Sheriff's office, Bexar County District Attorney's office, and Federal Bureau of Investigations (FBI) are ongoing.
"It's important to let the investigation go through its course so that we can ensure a thorough and complete review of all that occurred of the evidence and the actions of the officers," Bexar County Sheriff Susan Pamerleau said.