Jain reportedly confessed to her involvement in the alleged plot during a polygraph or a lie detector test conducted on her in Bangalore last week.
Naresh Pardesi, the alleged accomplice of underworld don-turned-politician Arun Gawli too had admitted that he knew of the plot to eliminate Bhandarkar, police officials said.
Pardesi made the confession in a narco-analysis test conducted on him in Bangalore last week, they said.
Jain was arrested Sep 10 and subjected to a polygraph test Sep 13 in Bangalore.
According to Pardesi, Bhandarkar reportedly paid money to Gawli to expose Jain's plans to the police.
Jain was accused of hiring the services of Pardesi for Rs.70,000 to kill Bhandarkar.
The duo's police remand was Wednesday extended till Sep 23, and a city court adjourned their bail pleas till then.
The police officer investigating the case told the court of Metropolitan Magistrate A.V. Shete that three more arrests had been made since the last remand of the accused and the police needed further time for their probe.
The court said full opportunity should be given to the police machinery for the probe and extended the custody of the accused.
Co-accused Gufran Mohammed Ibrahim Shaikh alias Sameer, arrested Tuesday night in the same case, was remanded in police custody till Sep 30 by the court.
Sameer, a sharpshooter, is suspected to be part of the conspiracy, according to police. Two others - Shivam Arjundas and Satish Mohite - too were arrested Tuesday.
Police claim Pardesi allegedly hired Shivam, Mohite and Sameer to execute the plan to kill Bhandarkar.