Guwahati, Oct 15 (PTI) The Assam CID Thursday arrested superintendent of police Kumar Sanjit Krishna, who is the brother of the state chief secretary in connection with the police exam paper leak scam in the state.

Krishna is the highest ranked serving officer of the Assam government arrested so far in the scam that has rocked the state, giving the much needed ammunition to the opposition just six months before the Assembly polls.

Krishna is the brother of chief secretary Kumar Sanjay Krishna.

A senior official told PTI that Sanjit Krishna was arrested by the CID after completing his medical check up, which was done following a series of marathon interrogation over the last few days.

"He will be produced before a court tomorrow and we will seek his custody," the official said .

Sanjit Krishna, who was suspected to be absconding on Wednesday, reached the state police headquarters here at around 11 am and was questioned by top Assam police officials the whole day, a source in it told PTI.

At around 6 pm he was detained and the CID sleuths took him to their headquarters, which is about 200 m away. His medical check up followed.

The senior police officer was interrogated for long hours on Monday and Tuesday too by the top brass of Assam Police.

Krishna was the SP of Karimganj district, where the question paper was allegedly leaked at his behest in his residence in the presence of other accused persons in the scam, some of whom have already been arrested.

The SP, who is a senior officer of the Assam Police Services, was transferred to Barpeta district as the superintendent of police of the Foreigners Regional Registration Office (FRRO) on October 11 which was a Sunday raising questions over the investigation.

His official residence at Karimganj was searched on Sunday and Tuesday, while his personal house her was searched by the CID on Wednesday.

Assam Chief Secretary Kumar Sanjay Krishna had said in a Facebook post on Tuesday that if his brother has done something wrong then "law will take its own course on the basis of evidence".

"As Chief Secretary, I have been supporting on independent and neutral enquiry from the beginning ... and I believe whoever is guilty will be brought to justice," he had added.

So far multiple agencies of the Assam Police have arrested 51 people from different parts of the state and outside it, including retired DIG Prasanta Kumar Dutta and BJP leader Diban Deka who was later expelled from the party.

The police have so far registered five cases across the state.

The CID has arrested 21 people so far, while the Nalbari police have taken in 14 others. The crime branch of Guwahati Police has arrested 11 persons and the Lakhimpur district police five others. There has been no arrest yet against the case registered at Diphu in Karbi Anglong district.

The CID had searched the house of Dutta's employee Jaydip Borooah, who was in hospital following detection of COVID-19 and seized 24,88,300, an Assam Police spokesperson said.

With this, nearly Rs 5.65 crore cash has been recovered from different places in the state in connection with the scam, he added.

On September 20, the question paper of the written examination for 597 posts of unarmed sub-inspectors in Assam Police was leaked and the State Level Police Recruitment Board (SLPRB) cancelled the test minutes after it had commenced across the state that day.

Around 66,000 candidates had downloaded their admit cards for appearing in the written tests in 154 centres spread over all the districts.

SLPRB Chairman Pradeep Kumar had later resigned owning moral responsibility for the scam and the state government had reconstituted the board with the director general of police as its chairman.