SAN ANTONIO (CBSDFW.COM) — Officials are investigating a possible case of human smuggling after dozens of people were found near an abandoned tractor trailer just outside San Antonio.

It was after 2:00 a.m. when police received calls about a suspicious trailer with loud banging coming from inside. When officers arrived at the scene, on the southwest side of the city, they found the trailer empty and requested  helicopter assistance. From the air dozens of people, believed to be undocumented migrants, were found hiding in nearby brush.

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Initially, police said nine women and about 20 men were being detained but later said some 40 people were in custody — their ages ranged from 17 to 32-years-old. Crews said medically the group was only suffering from dehydration and fatigue.

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In all, officials believe there may have been between 60 to 80 people inside the air conditioned truck that traveled in from Laredo. The search for others who fled continued in the area along Quesenberry Road Friday afternoon.

Police believe the group had been inside the back of the tractor-trailer for about 4 hours. The driver of the big rig has not been located.

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The Department of Homeland Security is taking over the investigation. Staff