The CID had taken up the case after reports of question paper "leak" surfaced from several districts of the state.
The official said that all the arrests were made late on Sunday night.
A total of 10,66,000 students are appearing in the class X school leaving examination conducted by the West Bengal Board of Secondary Education.
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Class XII students Sahabul Amir and Shahbaz Mondal from Malda and Katwa, respectively, and Sajidur Rahman fro Hooghly whose identity is yet to be known were arrested during several raids conducted by the probe agency's sleuths, the IPS officer told PTI.
"Five persons have been arrested in raids conducted Sunday from different parts of West Bengal. Two candidates of Madhyamik examination have also been apprehended. Raids are also being continued to apprehend others involved in the racket," the CID officer said.
He said the accused had opened a WhatsApp group for sending out images of the question papers.
The exam, which began on February 12, saw questions getting "leaked" via purported images on social media platforms on four consecutive days when English, Bengali, history and geography exams were conducted.
West Bengal Education Minister Partha Chatterjee had discounted reports of any question paper leak in the Madhyamik examinations.
"So far, it has been found that the questions were sent via phone for solving and dissemination of answers after the start of the examination," he said.
Some more people are involved in the racket, the officer said adding that the phone numbers used for the purpose were identified and a search for the owners have been initiated.
CID officials said the possibility of involvement of more students is not being ruled out at this stage.
Question papers for this years ongoing Madhyamik examinations were allegedly leaked through WhatsApp, sparking outrage among the students that forced the state government to initiate a CID probe into the matter.
With inputs from PTI
