The Central Board of Secondary Education (CBSE) office had received an unaddressed envelope on March 26 containing four sheets of handwritten answers of the Class-12 Economics paper, the Board informed the Delhi Police.
The Delhi Police's crime branch is probing the alleged leak of Class-12 economics and Class-10 mathematics papers.
Following reports of the CBSE Class-10 mathematics and Class-12 economics examination papers leak on Wednesday, two separate cases were registered in the matter. And the board announced re-examination of the two papers.
The first case in connection with the leak of economics paper was lodged on March 27 while the case pertaining to mathematics paper was lodged on March 28.
The CBSE, in its complaint to the police, said that they received a complaint by fax on March 23 from an "unknown source" that a man running a coaching institute in Rajinder Nagar was involved in paper leakage.
The complaint named two schools in Rajinder Nagar for their involvement in the alleged leakage of papers.
On March 26, the CBSE Academic unit at Rouse Avenue received an unaddressed envelope in the evening containing four sheets of handwritten answers of the Economics paper.
"It was indicated in the papers kept inside the envelope that the question paper was leaked and circulated through WhatsApp group numbers," the complaint said.
The cases were registered following a complaint by the regional director of CBSE. The cases were registered on charges of criminal breach of trust, cheating and criminal conspiracy.
A special investigation team comprising two deputy commissioners of police, four assistant commissioners of police and five inspectors has been set up to investigate the matter. The team will be directly supervised by the joint commissioner of police (crime).
A similar incident occurred on March 15, when the Delhi government had said that it had received complaints of the Class 12 CBSE accountancy paper being leaked. A probe was later ordered even though the board had denied any leak.
"There has been no leakage of the question paper. All the seals have been found intact at all exam centres. However, at local level, some miscreants may have circulated messages through WhatsApp and other social media platforms to hurt the sanctity of the exam," the board had said then.
(With inputs from PTI)