Meena Devi. (PTI)

Meena Devi, prime accused in the July 16 midday meal tragedy, underwent a polygraph test at Town police station in Chhapra on Friday.

The test on Meena (48), suspended principal of Dharmasati Gandaman Primary School, began on Thursday. She was subjected to a four-hour procedure on Thursday, another two-and-a-half hours on Friday and then sent to jail.

A two-member team of the Central Forensic Science Laboratory (CFSL), New Delhi, led by senior scientist A.K. Singh, conducted the test based on a questionnaire jointly prepared by Special Investigation Team (SIT) and forensic experts. Saran superintendent of police (SP) Sujeet Kumar, heading the probe team, said the CFSL team left for Delhi after completing work in the noon.

The SP said the team did not allow any police officer from the district to enter the room where the test was on. “The CFSL carried out the test in a closed room. It would submit the report to the state police headquarters within a week,” he told The Telegraph.

The SP said the test would help the police in the probe but admitted its findings were not admissible in court as evidence. “The test aims at crosschecking Meena’s statement on the incident after her arrest on July 24,” he said.

An officer associated with the probe said no external medicine was used. The principal was upset when she was brought to the Town police station from the divisional jail amid tight security on Thursday. “She was taken on a three-day police remand for conducting the test,” he said.

Sources claimed that forensic experts initially sought to know about her parents and in-laws, their profession and her educational background. She was asked simple questions in two sessions lasting 45 minutes each on Thursday. “She became a bit nervous after the team began hurling questions on the midday meal incident,” the officer said.

Experts sought to know about the pesticides stored in her room and the food materials purchased from the shop. She was asked to explain whether the cook’s daughter, who also died after eating the meal, used to fetch the cooking material from Meena’s house on a regular basis or was assigned the job that particular day.

Questions like her relationship with colleagues, family’s enmity with neighbours and parents of any student, her role in the incident, previous complaints about quality of food, her reaction after the incident, reason for her sudden disappearance from the spot and her family’s political links were also asked.