SAN ANTONIO (CBSDFW.COM/AP) — Dozens of people, including some children, were discovered inside a tractor-trailer in San Antonio.

Authorities from several agencies were called to a North Side neighborhood around 8:30 p.m. on Tuesday and found 55 people suspected of entering the country illegally in and around a tractor-trailer.

(credit: CBSDFW.COM)

Homeland Security Investigations spokeswoman Nina Pruneda confirmed the agency is investigating.

San Antonio Fire Department chief Charles Hood says all the people appeared to be in good health. “This truck was air-conditioned, thank God. This truck had water. So they were hydrated,” he said.

Hood says five individuals were treated for minor injuries. They were transported to a hospital.

Except for the five injured, all of the trailer’s occupants were taken to a detention center after they were searched.

So far investigators have not said where the people in the semi came from or where they were headed. The driver of the truck has been arrested.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)