Calcutta, Sept. 6: A group of students is suspected to have made a hoax call today warning of a bomb blast in Hedua’s Scottish Church Collegiate School, apparently to put off an oral test.

The test, for next year’s Madhyamik candidates, was held two hours after schedule after a bomb disposal squad from the Lalbazar police headquarters carried out a thorough search.

“We searched every corner of the school building with sniffer dogs. But we drew a blank,” an officer of Burtolla police station said.

The call was traced to a telephone booth near the school.

“The owner of the booth confirmed that a group of students in school uniform had made a call at that time,” an officer said.

The police said the call came at 10.30am, a few minutes before the oral test was to start. “It appears that the students wanted to get the examination postponed,” an officer said.

The police have started an investigation. “Based on the description provided by the owner of the booth, we are trying to identify the culprits,” the officer said.