A 17-year-old boy and his father, who were allegedly kidnapped from West Bengal's Narendrapur near the city and held captive for ransom, were rescued by the police from a BJP office-cum-storehouse, an officer said on Tuesday.
Three people were arrested in connection with the case.
A local BJP worker said the party had no knowledge of how the accused gained access to the building which houses the saffron party's election office and serves as a storage facility for party flags, furniture and campaign material.
The alleged abduction took place from the Narendrapur area on Sunday, he said.
According to the family, they received a phone call shortly afterwards demanding Rs five lakh as ransom for the release of the two.
"The family approached the Narendrapur Police Station immediately after receiving the ransom call. A case was registered, and multiple teams were formed to trace the victims. Based on technical evidence and sustained investigation, we located them and rescued them safely," he said.
As part of the operation, police asked the family to inform the callers that the ransom money was being arranged. The strategy led the police to a premises on Manoharpukur Road under the jurisdiction of Rabindra Sarobar police station in south Kolkata.
"Our team raided the premises, opened the shutter and found the father and son confined inside. Three people have been arrested. The motive and the role of each accused are being verified, and further investigation is underway," the officer said.
The victims were allegedly confined inside the premises for nearly 24 hours and were assaulted during their captivity. They have been rescued safely and are being medically examined, the officer added.
Denying any organisational link with the accused, the BJP said the premises was largely used as a warehouse and temporary election office.
A local BJP worker said the party had no knowledge of how the accused gained access to the building.
"It is essentially a warehouse where flags, chairs and tables are kept during elections. We are shocked that such an incident took place there. As far as we know, those arrested are local miscreants and have no connection with the BJP. They may have entered by breaking in or by using duplicate keys, but that is for the police to establish," he said.
Police said investigators were trying to ascertain how the accused accessed the premises, whether duplicate keys had been used and if anyone else was involved in the alleged kidnapping and wrongful confinement.