As per the complaint filed by CMO Anita Singh, a person claiming to be a personal assistant of the CM, called her on October 2 and demanded Rs 2 lakh from her, SP Ajay Kumar Sahni said.
The caller apparently threatened the CMO that he will get her suspended if she failed to give the money, he said.
The number was put on surveillance and was located near a hydel tri-section today, police said.
Sahni said that efforts were being made to arrest two more members of the gang.
