Take a look at the pictures. Agents at the Interstate 19 checkpoint in southern Arizona discovered the men after suspicions were raised when they attempted to cross into Arizona and were pulled over for further inspection.
Per the Tucson Sector Border Patrol, "Several of the subjects removed from the vehicles stated they had no knowledge of the trunk release mechanism. Although none of the persons involved were injured, traveling with a person in the trunk of a moving vehicle is dangerous due to heat, the possibility of a vehicle accident, or other unforeseen circumstances."
All five men were taken into custody, along with the three drivers. Their names were not released.
Despite high temperatures in the trunks, the men were not hurt.