They were nabbed from Ukhia, Teknaf and Sadar Upazilas in the early hours of Thursday.
The detainees are Khalilur Rahman, 38, Abdus Samad, 35, Adbul Hamid, 30 and Mohammad Jalil.
Police raided Tekparha at Cox’s Bazar town after getting information that Jalil, a suspected people smuggler, was at his home located in that area, said Cox’s Bazar Sadar Police SI Abdul Kayuum.
Meanwhile, angry relatives of human-trafficking victims from various parts of Ukhia detained Khalilur from Jaliapalang Union’s Lambariparha and handed him over to police.
After being informed of the development, detectives went there and detained him, said Detective Branch SI Emon Kaanti Chowdhury.
Two brothers - Samad and Hamid –were nabbed by police from Hariakhali of Sabrang Union.
They would be shown arrested in two cases filed against them over human trafficking at Teknaf Police Station, said Inspector Ataur.