The Crime Branch put dismissed assistant sub-inspector Gopal Das the prime accused in ex-minister Naba Kishore Das's murder case to forensic psychological assessment and LVA test after he was brought to police remand for four more days, a senior officer said.

Forensic psychological assessment is done to identify, operationally define, and measure a person's adaptive and maladaptive behaviours and treatment goals.

Similarly, the LVA test is done to ascertain various types of stress, cognitive processes, and emotional reactions that expose the emotional profile and sensitive discussion points of the accused.

"Forensic psychological assessment and LVA Test of accused Gopal Das is being conducted by a team of CFSL, New Delhi at Jharsuguda," the officer said on Saturday, adding that a special medical board has been constituted to study the mental health of the accused.

Accused Gopal Das's wife Jayanti has claimed that her husband was suffering from a mental disorder and taking medicine. His psychiatrist Chandra Sekhar Tripathy also corroborated Jayanti's claim.

Dr. Tripathy, who is head of the Psychiatry department, at MKCG Medical College and Hospital, Berhampur, had said , "Das was diagnosed to be affected to bipolar disorder about eight years ago. He had first visited my clinic about eight to ten years ago. He used to get angry very easily and was undergoing treatment for this."

Meanwhile, accused Gopal Das was produced in the Court of JMFC, Jharsuguda after completion of the first four days remand period on Friday. The court has allowed further police remand of four days, the officer said.

The Crime Branch team, which is camping in Berhampur also interrogated Gopal Das's wife more than five times. Gopal's elder brother Satya Das, nephew, relatives, friends, fellow villagers, and the doctor, who treated him for psychological problems, have also been questioned by the investigating officers.

The Crime Branch sources said that the assistance of handwriting experts is being taken to re-arrange the 22 pieces of torn papers recovered from the septic tank of the Airport police station at Jharsuguda, where Gopal was detained.

The accused has admitted the handwriting on the papers was his own. His diaries were also seized during searches in the locked official quarter and office desk of the accused at Gandhi Chhak police outpost, he said.

The minister Naba Kishore Das was shot at by Gopal Das in full public glare at Brajrajnagar in Jharsuguda district on January 29 and the minister succumbed to the bullet injury at a private hospital in Bhubaneswar later that evening.