The police have received complaints from three businessmen — the calls were made between December 15, 2008, and January 5 this year, and the demand was for Rs 5 lakh in each case. Investigators say the caller used “sophisticated language” and appeared to know every little detail about the victims and their family members.

According to police, the first threat call went out to Trilok Singh, owner of Kalra Sweets in Jheel (under Geeta Colony police station) on December 15. The call, as per the complaint, was short: “I am Babloo Srivastava and my gang specialises in extortion. I want Rs 5 lakh as protection money. If you refuse, I will keep a gun on your son’s head and you will then be happy to give me even Rs 20 lakh.”

In a sign that he had done proper homework, the caller reportedly also gave Singh his son’s school address.

The second call was made four days later: to Ashok Taneja from Taneja Sweets in Jheel. This time, the called identified himself as Ajay Pandit, an associate of Babloo. The message was similar. The ransom call was more specific this time — the caller said the money should be handed over at Karkardooma Court.

The calls to the third victims, the investigator said, were more “incisive”. They were made to Neeraj and Manoj Kumar, brothers who own Kumar Saris on Vikas Marg (under Shakarpur police station). They were made alternately on December 29 and 30, and January 1, 2, 3 and 4.

‘Babloo Srivastava’ demanded the same protection money — Rs 5 lakh — but each time he informed the brother receiving the call the colour of the sari his wife wore that particular day and the daily routine of his children. “After the third call, one of the brothers had to be hospitalised due to anxiety,” a senior officer said.

“He is now threatening to withdraw the complaint.”

Investigators said all the calls were made between 5 pm and 11.30 pm; different sim cards were used in each case — when called back, the sim was found to be destroyed.