CBI 5: The Brain

Aparna attends a CBI hosted seminar for IPS trainees, where DSP Balagopal and Inspector Vinay host the session. The program frames the Basket Killings case as a focal point and introduces the looming involvement of senior CBI officer Sethurama Iyer.

Home Minister Abdul Samad dies while traveling by aircraft from Delhi to Nedumbassery. The death is surrounded by suspicion, fueling calls for a deeper probe into possible foul play behind the Basket Killings.

Samad's doctor, Venu, is found dead under mysterious circumstances, triggering protests and intensifying demands for an investigation into Samad's death. The public discourse widens the scope of the Basket Killings case.

Protests escalate against the government, and journalist Bhasuran is murdered by hanging, followed by the murder of police officer Josemon in a hit-and-run incident. Authorities link these deaths as connected acts within the Basket Killings saga.

The case is handed to the corrupt DYSP Sathyadas, who clashes with Iyer and the CBI. Adv. Pratibha, Sathyadas' wife, leads a petition to transfer the case to the CBI, adding a layer of political maneuvering to the investigation.

Balagopal revisits the workload petition decision and pushes to withdraw it, aiming to facilitate a CBI takeover. Senior officials, including the DGP, are drawn into the push to reassign the case.

The investigation is formally handed over to the CBI and Iyer is summoned to Kerala to lead the inquiry. He reconnects with Kerala officials and aligns with the local CBI office for the case.

Iyer learns that a youth named Mansoor, related to Samad, joined a militant group years earlier. This link broadens the inquiry toward militant ties and political connections around the minister and the Chief Minister.

Investigators probe Sam and his circle, including Adv. Pratibha. Samad’s death is scrutinized as potentially accidental, with clues pointing toward the possibility that the intended target was Susan, a patient of Dr Venu. The investigation begins threading together medical and political connections.

A lead from Delhi Airport CCTV identifies a man named Sandeep, connected to DYSP Vikram, a murder target. He is later revealed to be Paul Meyjo, a figure tied to Ray the pacemaker notes and the broader conspiracy.

Meyjo explains that he crafted designs to hack pacemakers to counter Dr. Venu’s claim, but the lack of conclusive evidence leads to his release. The absence of decisive proof leaves the conspiracy shrouded in ambiguity.

Iyer pieces together the case and uncovers that Abdul Samad’s murder involved orders from Sam and Unnithan. Susan is revealed as Ambika, Unnithan's ex-wife, linking the personal and political abuse behind the killings. Unnithan is arrested but dies of a heart attack during the trial.

In a tense post-arrest moment, Meyjo corners Iyer in prison and warns that Iyer is his next target. Iyer remains self-assured, mentioning Vikram and the persistent danger as he walks away, leaving the ending with a chilling unresolved tension.