The man who apparently alerted police about Rakesh Singh’s alleged conspiracy to frame a woman in a narcotics case two days before Pamela Goswami’s arrest, and who later became a witness in the cocaine case, has sought police protection.

S. Agarwal has written to the police citing specific instances during morning walks in a Salt Lake neighbourhood when he felt insecure and has requested police protection, a senior police officer said.

In the letter, Agarwal has expressed his apprehension that his life was under threat from Rakesh Singh’s men and that he feared an attack on him the moment Singh is out (of jail) on bail.

“He has cited a specific incident in a Salt Lake neighbourhood where he has mentioned a particular person who identified Agarwal in public as someone who was helping the Calcutta police headquarters. He has written that this man categorically said that as he (Agarwal) was helping police against Rakesh Singh, he would soon be in trouble,” the officer said.

Senior police officers said cases of witnesses feeling intimidated or threatened are common but the person had shown rare courage by reporting the matter to the police.

Agarwal had first written to Lalbazar on February 17, two days before officers of New Alipore police station received a “tip off about the presence of cocaine” in a vehicle belonging to BJP youth leader Pamela Goswami.

Cocaine weighing 90 grams was allegedly seized from her car following her arrest in New Alipore on February 19.

Soon after her arrest, BJP leader Rakesh Singh’s name had emerged during investigation and the police connected the incident to the mail they had received on February 17.

In the mail, Agarwal had mentioned about his estranged wife Amrita Singh (who was later arrested in the cocaine case) and her alleged links with Rakesh, police sources said.

The police had contacted Agarwal and made him a witness in the case.

His statement was recorded before the magistrate under 164 of the CrPC — which is treated as primary evidence in court.

The police has a witness protection scheme for helping witnesses who seek protection, another senior officer said.