Authorities say 46 people were found dead inside a tractor-trailer near San Antonio, Texas, as the temperature topped 100.
At least a dozen others were taken to hospitals after the rig was found abandoned on the outskirts of the Texas city.
Zachary Taylor Blood was busted smuggling two men from Mexico after Border Patrol agents noticed a U.S. flag carelessly taped to the coffin.
A good Samaritan called the Coast Guard early Tuesday after rescuing a man clinging to the boat 45 miles east of Fort Pierce.
"It is important that we now act quickly."
The gang gave fake asylum registration documents to migrants in exchange for about $3,400 each.
Dozens of bodies were found at the smugglers' jungle camps.
Much is said about the difficulties undocumented immigrants face due to the recent security measures taken in the Mexico-U.S border, but little attention is devoted to the role that Mexican drug cartels have played in reshaping the human smuggling dynamics in the last few years.