The Edinburg Police Department confirmed that 17 immigrants were in the back of the trailer, KRPC reported.
There were no ambulances observed on the scene, and Edinburg police did not report any injuries or casualties. He reported that the trailer was getting too hot inside for them, according to reports. The locked trailer was in the parking lot of a "Flying J" convenience store, according to Fox 8.
A KRGV-TV reporter said Edinburg police had found 17 immigrants in the trailer.
The U.S. Border Patrol is investigating the incident.
According to an NBC affiliate, a man and woman who were in charge of the trailer were detained.
Before being taken into custody, The Monitor observed a group of more than 10 individuals sitting in a shaded area underneath a tree. Robert Rodriguez, a Public Affairs Supervisor for Border Patrol, said they are still gathering details.
This is a developing story.