18 undocumented immigrants were discovered inside a near-freezing tractor trailer in Arizona on Monday.

The incident happened on October 22nd in Nogales, Arizona.

According to the Arizona Daily Star, a semi truck passing through the Interstate 19 immigration checkpoint was sent to secondary inspection after a K9 alerted to a suspicious scent on the rig.

Upon investigation of the big rig, agents discovered 18 illegal aliens inside the refrigerated trailer ranging in age from 15 to 40.

The illegal immigrants, two from Guatemala and 16 from Mexico, were being kept in temperatures of 36 degrees but all seemed to be in good health at the time of the discovery.

The 47-year-old unnamed driver was arrested and the 18 undocumented immigrants were taken into custody and processed for immigration violations. The driver is currently facing federal smuggling charges.