Former India cricket captain Sourav Ganguly and his wife Dona have become the target of death threats, prompting Kolkata Police to launch an investigation after the Cricket Association of Bengal (CAB) president filed a written complaint, news agency PTI reported.

Ganguly lodged the complaint at Thakurpukur Police Station in south Kolkata after two letters arrived at his office on Monday, a senior police officer confirmed. The letters contained explicit threats to kill Ganguly and his wife and to harm people close to him.

Six months of threatening letters

According to the police complaint filed by Ganguly's manager, the letters had allegedly been arriving in the former India captain's name for around six months. They were initially not taken seriously, but the two letters received at his office on Monday escalated matters significantly.

"We are taking the complaint seriously and have begun an investigation. We are examining the letters, their source and the courier trail to identify the person responsible," a senior police officer said.

Police track courier trail

The preliminary investigation suggests the letters may have been sent through a courier service, allegedly by a person from Belgharia in North 24 Parganas district. Police are also examining the movement of the SIM card allegedly used by the sender and have contacted the courier agency to collect details about the consignments.

"We have spoken to the people from the courier service and tracked down one mobile number. We are trying to spot it," the officer said.

Investigation into motive

Kolkata Police are now checking whether all the letters were sent by the same person and are trying to establish the reason behind the alleged threats. Investigators are examining the contents of the letters, their source and the courier trail as part of the ongoing probe.

Ganguly, one of India's most celebrated cricketers, led the national team to numerous historic victories before taking on administrative duties as president of the Cricket Association of Bengal.