Vyapam, set up to conduct entrance examinations for professional courses in 1982, has been the epicentre of a Rs 3,000 crore scam involving the Education Minister in the previous BJP-led Shivraj Singh Chouhan government. Many layers have been peeled off so far and the revelations would continue with the incumbent Congres government keen to go ahead with further investigation.

In another revelation on Wednesday, videos concerning former Education Minister and key accused in the scam Laxmikant Sharma, who was also caught in the honey trap case, have provided more ammunition to the Kamal Nath government. A government spokesperson said the videos would be used to delve further into the matter.

The Vyapam scam refers to irregularities in exams held by the the Madhya Pradesh Professional Examination Board (MPPEB) for admission in professional courses and state services over several years. The scam hit national headlines in 2013.

Thursday's verdict relates to the accused who were found guilty on a host of counts, including cheating by impersonation, cheating and forgery related to 2013 police constable exam conducted by the MPPEB, better known by its Hindi acronym Vyapam (Vyavsayik Pariksha Mandal), the prosecution said.

Of the 12 impostors writing examination on behalf of other candidates, six each were arrested from Bhopal and Datia then.

CBI special judge S.B. Sahu convicted the 31 accused, including 12 impostors and seven middlemen, said CBI special prosecutor Satish Dinkar.

The prosecution produced 91 witnesses and evidences to nail the culprits for cheating by impersonation, cheating, dishonesty, forgery, forgery for cheating and forging documents under IPC sections 419, 420, 467, 468 and 471, Dinkar added.