Sanjay Singh, who plotted the March 9 abduction of Pratik Gupta, was arrested late on Wednesday.

Ajay Singh, a member of Sanjay’s racket, has been picked up from a village in Bihar’s Ara district. Police said Ajay guarded the Titagarh hideout where the SN Banerjee Road resident was kept hostage.

Ten other members of the gang, including Sanjay’s wife Preeti, had earlier been rounded up in connection with Pratik’s abduction.

Police said Sanjay, picked up from Colootolla Street, had masterminded the abduction of the 20-year-old using a Delhi-based woman, Saheen Mehta, as bait.

“Saheen stayed in a house in Jhangra, off Rajarhat, with Sanjay and his wife. We will interrogate him to find out details of his other abduction plans,” said Jawed Shamim, the deputy commissioner of police (detective department).

“Sanjay, who was a pimp, was arrested in 2000 on an abduction charge. Following his release on bail, he went to Gujarat and Delhi to try and build a crime network,” said an officer of the detective department.

The sleuths are looking for the woman to whom Pratik’s father had handed over the ransom amount of Rs 20 lakh.