The National Institute of Technology here on Wednesday said Jolly Joseph, who was arrested in connection the death of her husband following consumption of cyanide-laced food, was neither a temporary or permanent employee of the institution.

"We have checked NIT records since the year 2000 and Jolly was not an employee at the institute. She was not even employed as temporary employee," NIT Registrar, Lt Col (Retd) Pankajakshan said.

The investigating officers had made a confidential visit to the campus a month ago to gather details of Jolly, who had claimed for years that she was a lecturer at the institute.

Jolly, a commerce graduate, had told her relatives and friends that she was working in the NIT and used to travel by car to the college daily.

Eight years after her first husband Roy Thomas's death following consumption of cyanide-laced food, police had arrested Jolly and two others on Saturday and started investigations into the death of five others of the family between 2002-16. Jolly married her husband's relative Shaju in 2017.

Shaju was questioned for almost the whole day on Monday and was let off after his statement was recorded.

The investigation into the suspicious deaths in Roy's family began after his US based younger brother approached police complaining that the post mortem report had revealed traces of cyanide.

The remains of the other relatives were also exhumed for examination.

Police on Wednesday questioned a BSNL employee, Johnson, who is suspected to have provided SIM cards to the woman.

Her call details also revealed that she had made several calls to Johnson during the past few months.

Police has also approached a court here seeking custody of Jolly and two others for 11 days.