U.S. Border Patrol took the six immigrants into custody on Friday morning.
Investigators told Action 4 News that they were dropped off outside the Walmart in Mission.
Border Patrol agent Danny Tirada said agents at the McAllen station received a call at about 8 a.m. on Friday.
The caller said approximately 20 people had been dropped off at the parking lot of the Walmart.
When agents arrived, they were only able to find six of them.
All six were transported to a Border Patrol station and processed for deportation.
Their gender, ages and countries of origin were not available as of Saturday night.