New Delhi (CNN) -- The headmistress of the Indian school that authorities say served toxic lunches, killing 23 students, was arrested Wednesday, police said.
Meena Kumari, 36, was taken into custody on her way to a court where she had gone to surrender herself, police Superintendent Sujeet Kumar told CNN. She will be questioned Wednesday and taken before the court Thursday, he said.
Authorities had been working to track down Kumari, who had been at large since the July 16 incident.
The whereabouts of her husband, who is not named as an accused person in the case, are still not known, Kumar added. Police want to question him in connection with the case.
Pesticides have been found in the food and oil used in the school lunch that sickened 25 others in northern India's Bihar state, police said.
A woman rests with her child at a ward housing the poisoned schoolchildren at the Patna Medical College and Hospital, in the eastern Indian state of Bihar, Wednesday, July 17. At least 22 schoolchildren died in northeastern India after eating free school lunches that contained an insecticide commonly used in agriculture. Officials are investigating whether the poisoning was accidental or deliberate. Books, papers and dishes are seen scattered on the floor after the incident. An Indian man mourns as he holds his dead daughter inside an ambulance, outside a hospital in Patna. The deaths triggered violent protests in Chhapra, the headquarters of Saran district. A grief stricken mother is consoled after the death of her son. Villagers gather for a funeral for children who died from the poison. Deadly school lunch in IndiaDeadly school lunch in IndiaDeadly school lunch in IndiaDeadly school lunch in IndiaDeadly school lunch in IndiaDeadly school lunch in IndiaHIDE CAPTION<<< 1 2 3 4 5 6 >>>
Deadly school lunch in India
Indian headmistress found and arrested
Inside an Indian school kitchen
Free lunches halted at Indian schools Forensic scientists found monocrotophos, an organophosphorus compound used as an insecticide, "in the samples of oil from the container, food remains on the platter and mixture of rice with vegetables in an aluminum utensil," Assistant Director General Ravinder Kumar told reporters in Patna.
Monocrotophos, which is used for agricultural purposes, is toxic to humans.
Bihar's chief minister, Nitish Kumar, vowed that police would investigate the poisoning incident from all possible angles.
"It does not appear to be mere coincidence or negligence," he told reporters after Kumari's arrest. "Police investigation will reveal everything."
Confusion, grief and despair in India's school poisoning village
The chief minister said forensic tests showed that pesticide levels in the food concerned were too high.
"The main accused (principal Kumari) is now under arrest, and every aspect of the case will be investigated," he said.
The child survivors of the incident were hospitalized in stable condition, and Nitish Kumar said he had advised that they be kept under medical care longer.
A cook, Manju Devi, was also hospitalized after eating the food she prepared, doctors said.
Mom anguishes over child poisoned by lunch
Devi told police that the headmistress did not heed her warning that the mustard oil used to prepare lunch looked and smelled bad. Instead, the headmistress insisted she continue preparing the meal, officials said.
Authorities previously said police would ensure the headmistress' safety when she was found.
The children's deaths prompted angry demonstrations from residents.
In acts of protest, parents of at least three victims have buried their children near the government-run school -- one right in front of the building, according to officials.