A Border Patrol K9 alerted agents to a trailer loaded with undocumented immigrants at the Falfurrias checkpoint.
A 55 year old man was referred to secondary inspection where 25 undocumented immigrants were discovered inside.
An unaccompanied child from Mexico was among the group, along with an MS-13 gang member from El Salvador.
The driver was arrested.
The immigrants were from Mexico, El Salvador, Guatemala and Honduras.