Indian spy agency, the Research and Analysis Wing's (RAW) former chief Sanjeev Tripathi Tuesday joined the Bhartiya Janata Party (BJP).Tripathi joined the party in the presence of BJP president Rajnath Singh.A 1972-batch Indian Police Service officer, he was the chief of the RAW from Dec 30, 2010, to Dec 29, 2012, and hails from Bareilly in Uttar Pradesh."Our nation needs a stable, strong and decisive government and instability of any kind will not just be harmful for the economic development but will come to the aid of such forces who want to destabilise the country," Tripathi said after joining the party.He is the latest addition to the list of former bureaucrats to join the BJP, after former home secretary R.K. Singh, former petroleum secretary R.S. Pandey and India's former permanent representative at the UN Hardeep Singh Puri.