Rat poison was allegedly mixed in the water supply at a madrasa in Uttar Pradesh’s Aligarh district that is run by former Vice President Hamid Ansari’s wife Salma, The Times of India reported on Monday. The Al Noor Charitable Society, headed by Salma Ansari, handles the Madrasa Chacha Nehru.

On Sunday evening, a student is believed to have seen two unidentified men pouring some substance into the water cooler kept near the gate of the madrasa, the Hindustan Times reported. One of the men allegedly threatened the boy with a gun before the two escaped.

After an inspection, the substance was found to have been rat poison, the Hindustan Times reported. The water samples have been sent for forensic tests.

The Aligarh police has lodged an FIR against unidentified people under relevant sections of the Indian Penal Code, including Section 328, for causing hurt by means of poison.

“Following the incident, we have decided to install CCTV cameras in the 18-year-old charitable institution which has 4,000 students on its rolls,” Salma Ansari told The Times of India.