Patna, July 25 (IANS) A Bihar court Thursday sent Meena Devi, the principal of a government primary school in Saran district where 23 children died after eating contaminated food last week, to judicial custody till Aug 5, and allowed subjecting her to a polygraph test, police said.

Saran Superintendent of Police Sujit Kumar said she was presented, amid tight security, before the chief judicial magistrate who sent her to judicial custody and permitted the police to subject her to the lie detector test.

Meena Devi, the principal of the school at Gandaman village, was arrested by the Special Investigation Team Wednesday and interrogated by police officials.

According to police, she claimed innocence and denied her involvement in the tragedy.

Seeking permission for her polygraph test, police said in their application: "If court gives permission for it, police will take her on a remand."

A first information report (FIR) was registered against her on penal charges of murder and criminal conspiracy, police said.

Meena Devi, who was suspended from service for gross negligence, was allegedly evading arrest from the day of the incident July 16, police said.

Police raided her house twice and recovered a bottle of pesticide whose traces were suspected to be present in the school food.

According to district officials, Meena Devi had forced the cook to use an allegedly contaminated cooking oil despite the latter's complaint that it had a pungent smell.

A forensic lab report confirmed presence of toxic insecticide traces in the cooking oil used for making food at the school, police said.

The poisonous substance, organophosphorus, in oil samples collected from school was more than five times the commercial preparation available in market, police said.