Known for his administrative acumen, former Union Home Secretary and Lok Sabha member Raj Kumar Singh, who was inducted on Sunday as Minister for Power, New and Renewable Energy at the Centre, was instrumental in the arrest of BJP leader L.K. Advani in 1990 in Bihar.
The 1975-batch Indian Administrative Service officer, who joined the Bharatiya Janata Party after his retirement in 2013, was the District Magistrate of Samastipur in Bihar when in October 1990, on then Chief Minister Lalu Prasad's orders, he was tasked with the arrest of Advani.
Advani was at that point in time taking out a Rath Yatra in the state en route to Ayodhya in Uttar Pradesh from Somnath in Gujarat to build up a popular movement in favour of a Ram Temple at Ayodhya.
Raj Kumar Singh's official action, however, did not come in the way of Advani who picked him for the post of Joint Secretary in the Home Ministry from 1999 to 2004, when the National Democratic Alliance (NDA) was in power.
Later, the officer served as Union Home Secretary under the Congress party-led United Progressive Alliance government from June 30, 2011, to June 30, 2013.
Raj Kumar Singh has served both in Bihar and at the Centre in different capacities, including as Secretary of Defence Production in the UPA government, and head of the Bihar government's departments of Home, Industries and Public Works.
He successfully contested the 2014 Lok Sabha poll from Arrah. He is known for his contributions to schemes for modernisation of police and prisons, and laying down a framework for disaster management.
It was during the officer's tenure as Union Home Secretary that Mumbai attack terrorist Ajmal Kasab and Parliament attack case convict Afzal Guru were hanged.
As Union Home Secretary, Raj Kumar Singh also oversaw alleged saffron terror cases involving blasts in Malegaon in Maharashtra and the Samjhauta Express train in Haryana and courted controversy by releasing the names of some suspects.
He also handled as the Home Secretary the public outrage after the December 16, 2012, gang rape of a Delhi woman.
It is said that the then Home Minister P. Chidambaram was very impressed by Raj Kumar Singh's efficiency and believed he was the man for the job.
However, on his retirement, the former top bureaucrat chose to join the BJP amid much fanfare, expressing his admiration for the party's approach on issues of national security.
He had criticised the distribution of BJP tickets during the 2015 Bihar assembly elections, which the party lost.
However, with his induction in the Modi governmenet, Raj Kumar Singh seems to have made up with the leadership and he has been rewarded for his administrative acumen.
A well-read man, he studied English literature at St. Stephens College, Delhi, and got a Bachelor's degree in law thereafter.
He also studied at the RVB Delft University in the Netherlands. Before joining the IAS, he was selected to the Indian Police Service, where he served for one year.
He landed himself briefly in controversy when he criticised the then Home Minister Sushil Kumar Shinde, his former boss, after joining the BJP. The Congress reacted sharply to this.
Raj Kumar Singh was among the four former bureaucrats who were sworn in as Union Ministers in Sunday's reshuffle. He got the Power, New and Renewable Energy portfolio, earlier held by Piyush Goyal.