Two anonymous telephone calls were received at Mamata Banerjee's residence on Monday threatening to kill her, though the Trinamool Congress leader was at Delhi at that time.
Police Commissioner Gautam Mohan Chakraborty told PTI that two anonymous telephone calls, one at 1.43 pm and the next one shortly afterwards, were received on her landline number at her Kalighat residence.
The anonymous caller threatened to kill her, he said, adding an investigation is on.
The Trinamool supremo had earlier received SMS threats on her mobile phone on August seven, party sources said.
Trinamool Congress leader and Leader of the Opposition Partha Chatterjee said a complaint has been lodged with the local police station.
"We have lodged a formal complaint with the Thana police, but we don't have any trust on the city police. We can't expect any outcome of its investigations in the case," he said.