Patna, June 8 (IANS) Sensing trouble over ongoing investigation into Class 12 merit list muddle, Bihar School Examination Board Chairman Lalkeshwar Prasad Singh resigned on Wednesday, officials said.

"Under pressure to quit, Singh has resigned," an official of the education department said.

According to reports, a special investigation team of Bihar Police probing the case after an FIR (first information report) was lodged, is likely to detain Singh for interrogation.

"Some evidences suggest Singh's involvement into the merit list muddle that defamed the state like never before," an SIT official told IANS here. Raids are being conducted to detain Singh but he is missing now, the official said. "Neither he is available at his official bungalow nor in his official chamber." Meanwhile, the SIT on Wednesday detained seven persons, including four staff members of two high schools, in connection with the case.

The team began an investigation soon after a police complaint or an FIR was lodged against those declared as toppers in the board's Class 12 exams.

Chief Minister Nitish Kumar, who held a high-level meeting with top officials on Monday, expressed disappointment over the results and directed the officials to lodge an FIR and probe the matter as a criminal case.

In the FIR, it was alleged that fraud and machination were committed to influence the results, the police said. "The answer books of the toppers appeared to have been changed which makes it a case of fraud."

According to the police, the SIT has detained examination centre superintendent Sail Kumari, the head clerk and a peon of G.A. High School in Hajipur, district headquarters Vaishali.

The team has also detained the principal of Rajendra Nagar High School in Patna for interrogation.

Besides these four, the SIT has detained three others in this connection.

G.A. High School was the exam centre of V.R. College. All the answer books from Vaishali went to Ara and Bhabhua districts except for V.R. College which were examined at Rajendra Nagar High School in Patna.

"The team has also quizzed three board officials late on Tuesday," a police official said.

The team has raided some places in Vaishali and Muzaffarpur to arrest Amit Kumar alias Bachcha Rai, principal of V.R. College, who is considered main brain behind the muddle.

Amit Kumar has been missing and on the run since the SIT conducted searches at his college on Tuesday and seized some documents.

Those named in the case (FIR) include science stream toppers Saurabh Sreshtha, Shalini Rai and Rahul Kumar, arts topper Rubi Rai and principal-cum-director of V.R. College. All the toppers were students of the same college.

The board on Saturday cancelled the result of first and third toppers in the science stream as both failed their re-test, and since she did not turn up, decided to give the arts topper another chance to appear for a re-test on June 11.

The board received a report on re-assessment of 13 of 14 toppers of the Class 12 examination to find out if they really deserved their high grades or had cheated their way to the top.

Lalkeshwar Prasad Singh had said the government has cancelled the recognition of V.R. College.