Kalyani, May 1: A second-year student of the Indian Institute of Science Education and Research Kolkata today allegedly committed suicide by hanging himself in a hostel toilet.

Sagar Mandal, 19, was found dead this afternoon in the fifth-floor toilet on the campus at Mohanpur, near Kalyani, by his classmates. The students called police, who have registered a case of unnatural death.

The teen was last seen in his first-floor hostel room around 2.30am, a student said on condition of anonymity. He and other students were studying till late for an exam today.

"It appears that he subsequently went to the fifth floor, where there are a number of newly constructed, unoccupied rooms. We had an exam and we were all busy with our last-minute preparations. This morning we found he was missing and then we started looking for him. We found him hanging in one of the toilets on the fifth floor," the student said.

The students started looking for Sagar after they found he had skipped today's exam that was from 10am to 1pm.

Sagar's father Susanta Mandal is a mason working with a construction firm in Calcutta. The family lives in Fatehpur village in Haringhata, near the campus.

Additional superintendent of police, Kalyani, Swati Bhangalia, said: "Preliminary investigation suggests that the boy committed suicide. We have started a case of unnatural death. We have so far received no complaints from the parents of the boy. However, we will look into all aspects to find out the possible reason behind the suicide."

The body has been taken for a post-mortem.

IISER Kolkata director R.N. Mukherjee said: "We are shocked at the death of our student. We don't know why he took such a step. We will talk to the students to find out if they have any problem."

Tuesday's examinations have been postponed after the first suicide by a student at the institute, which opened a decade ago.

Dean of students' affairs Arindam Kundagrami said: "Tomorrow's examinations will be held on Sunday. However, normal classes will be held. We will also hold a condolence meeting on the campus."

Kundagrami added: "We have a counselling unit.... Sagar had no visible problem. We, however, will talk to the students.... But at the same time students should also understand that sufficient time is required to develop infrastructure and IISER Kolkata is still in a developing stage."

Sagar's father said, "I have no idea whether my son had any problem. I will talk to his friends."