The special investigation team (SIT), probing the Bihar Staff Selection Commission clerical grade exam paper leak, will focus on the website link from where the solved answer sheets of the question paper were circulated.

A senior police officer, investigating the case, claimed that most arrests made till date were of those who had helped in leak of the question paper and its circulation. But the SIT was yet to identify the nexus behind the solved answer sheet leak.

"If we reach the people behind the answer sheets, we will reach the scam kingpin. The answer sheet is highly confidential with only select people from the commission knowing where the question paper and the answer sheet are printed. So we can reach the bottom of the case."

A week before the first phase of the clerical grade exam held on January 29, two handwritten answer sheets, one for paper to be held on January 29 and other for paper to be held on February 5, was circulated on social media.

The January 29 solved paper was circulated on social media websites under the name "Kanpur series", while the second-phase examination (February 5) paper was labelled "Piyush Granthi".

Sources in the police said around solved answers of 140 (circulated on social media) of 150 questions matched the actual answers.

They added that different experts set a series of questions and answers. The officer said: "The answer sheets were either leaked from the commission office, the printing press or from the treasury where question and answer papers are stored."