CBSE had received an unaddressed envelope on March 26 containing four sheets of handwritten answers of the Class 12 Economics paper, the Board said in its complaint to the Delhi Police

The Delhi Police's crime branch is investigating the alleged leak of Class 12 Economics and Class 10 Mathematics papers after registering two separate cases in the matter.
    
In the wake of reports claiming paper leaks, the CBSE had on Wednesday announced re-examination of the two papers. In its complaint to the police, the Board has 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 also named two schools in Rajinder Nagar for their involvement in the alleged leakage.  On March 26, when the students sat for the Economics paper, 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 Delhi Police said they have registered two cases. 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, 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).
    
Reports about the economics paper being leaked had circulated on social media, including on WhatsApp, several hours before the paper commenced on Monday.
    
The CBSE, however, denied any leak and urged students and parents not to panic. 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.