The SIT also arrested former Board Chairman Lalkeshwar Prasad and his wife and former JD-U legislator Usha Sinha from Varanasi in Uttar Pradesh. Both are currently lodged in Beur Jail here.

Before that, SIT arrested Bachcha Rai, the alleged kingpin of the scam. Rai is director cum principal of the VR College in Vaishali district. He is lodged in jail as well.

The SIT had already arrested Class 12 'topper' in Arts, Rubi Rai, who said political science is all about cooking, after she failed in re-test. Her result was also cancelled.

So far, nearly 20 people have been arrested in the case, police said.

The scam surfaced after Aaj Tak TV channel showed a sting in which two Class 12 toppers could not answer even elementary questions about the subjects they 'topped' in.

The sting showed Rubi Rai, who topped the Class 12 exam in the Arts, saying: "Prodikal (read political) science is about cooking."

It also showed Saurabh Shreshtha, a Science topper, saying: "Most reactive element in the periodic table is aluminium."

Both Rubi Rai and Saurabh Shreshtha belonged to Bachha Rai's V.R. College.

The sting suggested that education in Bihar continues to be a very dubious affair with the possibility that cheating and fraud continue on a large scale with official connivance.