The Central Bureau of Investigation (CBI) on Monday began probing the murder of RTI activist Shehla Masood and said it would first "recreate" the sequence of events at her house in Bhopal.
On Aug 16, Masood, Madhya Pradesh chapter head of citizen's movement India Against Corruption, was shot dead inside her car outside her house.
Sources in the premier investigation agency say they will grill Bharatiya Janata Party (BJP) Rajya Sabha member Tarun Vijay and Bhopal legislator Dhruv Narayan Singh, apart from Inspector General of Police Pawan Srivastava in the case.
The three have already been quizzed by the Madhya Pradesh police on the basis of Masood's mobile phone call details.
While Vijay and Singh were known to be close to Masood, Srivastava had allegedly threatened the RTI activist about which she had also written to police in 2008 and 2010.
Sources say that Vijay had spoken to Masood only half an hour before she was killed.
Meanwhile, Masood's father Sultan Masood thanked Madhya Pradesh chief minister Shivraj Singh Chouhan for handing over the case to CBI. "Now our hope of getting justice has risen," he said.