They were forced to parade around the village with their hands and waists tied up with ropes on Friday and then taken to the office of local UP chairman Miranul Islam.
The UP chairman reportedly beat them up when they were taken there.
As their physical condition deteriorated, the injured were handed over to police and they took them to Chakaria Hospital for treatment.
The incident took place around 2pm on Friday at Paharchanda of the union.
As the horrific incident came to light after the photos of the victims went viral on social media, it triggered furor in the neighbourhood and elsewhere in the country.
Meanwhile, Deputy Commissioner of the district Md Kamal Hossain said a three-member probe committee has been formed to investigate the incident.
The trouble began when Mahbubul Haque, a resident of Bandabonkhil village, filed a case against the woman and her three children, and another person on Friday night.
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The “accused” are Parvin Akhter, 55, wife of late Abul Kalam of ward No-9 at Kusumpur union of Shantirhat in Patiya, her two daughters Selina Akhter Seli, 25, Rozina Akhter, 20, and son Emran, 23, and Mohammad Chottu, son of Delwar Hossain of Barbakia in Pekua upazila.
The woman along with her daughters and son were sent to Cox's Bazar district jail on Saturday afternoon through the Chakaria Senior Judicial Magistrate's Court.
According to the case statement, an anesthesia spray and a knife were recovered from their possession.
Aminul Islam, an inspector at the Harbang Investigation Centre of Chakaria Police Station, who rescued the victims from the chairman’s office said he sent force after receiving information from locals. The force rescued the mother and daughters in critical condition and took them into their custody. Later, they were given treatment.
He also said they have been made accused in a theft case.
Asked whether they were tortured under the supervision of Harbang Union Parishad chairman Miranul Islam, Aminul Islam said no one has made such complaint. When the police force went to the scene, there were about 200 people, he said.
“We had given priority for bringing the victims under our custody. There was no scope to know what happened there. Neither the victims nor anyone else made any complaint. Action will be taken after investigation,” the inspector added.
However, a number of witnesses said some youths, known in the area as the “chairman's men”, tortured them.
Then a chowkidar (village police) sent by Harbang Union Awami League president and UP chairman Miranul Islam tied them with ropes and brought them to his office and brutally tortured them again, they said.
But the UP chairman denied the allegation of beating the five people saying he was not there at the scene. “I returned from Chattogram and found them in my office and handed them over to the police,” he said.
Chakaria Police Station OC (Investigation) Mizanur Rahman said, “I don't know the details about the incident. Police at Harbang Investigation Centre brought three women and two men with stolen cows.”
They were sent to jail in a theft case. Among the “accused”, four are from the same family, the OC added.
Additional Superintendent of Police of the district Mohammad Iqbal Hossain said the Chakaria Police Station has been instructed to look into the matter.