Raja Bhaiyya has served as minister in the cabinet of Kalyan Singh and Ram Prakash Gupta - both BJP chief ministers.
The move to reinduct the Kunda legislator is also seen as a move by the Samajwadi Party leadership to quell the growing dissatisfaction among the Thakurs.
Talking to reporters after being sworn in, Raja Bhaiyya said he was pleased that he is back in the ministry and thanked chief minister Akhilesh Yadav and SP chief Mulayam Singh Yadav for their "sneh aur vishwas (love and trust)".
He also said he had always maintained that he had nothing to do with the murder of the police official and had in fact volunteered to undergo a polygraph test. He came out clean in the lie detector test.
