Unlike the police forces, the CBI's sole focus is investigation of cases handed over to the agency by the courts and approved by the central government.

After the UP Police bungled the investigation, Vandana Talwar had hoped the CBI would step in and repair the damage.

All of the UP Police's fanciful theories have a single point of origin: Rajesh Talwar's compounder, Krishna.

CBI officer Arun Kumar traced a call made to Hemraj's phone to Jalvayu Vihar -- close to Krishna's home.

Listen to Krishna's confession about Hemraj's phone.

CBI investigator AGL Kaul proffered the only element missing to implicate the Talwars: a luridly suggestive motive.

Plot thickened when Noida double murder was assigned to a new CBI team. There was new evidence in form of Rajesh Talwar's golf club. Send us your feedback at trialbyerror@arre.co.in