Former governor and CBI chief Ashwani Kumar was found hanging in his residence in Shimla on October 7, Shimla superintendent of police Mohit Chawla said.
Himachal Pradesh police chief Sanjay Kundu said that the investigation in the case was underway and a team of forensic experts have collected all the necessary evidence from the site.
Police said that a note, appears to be written by Kumar, was also found.
Retired police officer AP Singh, who succeeded Kumar at the CBI, referred to Kumar's death "absolutely shocking".
"I have worked closely with him as a special director. He was a gentleman. Never lost his temper. I always found him very pleasant, soft spoken; he never ever said a word to anybody in a raised voice," AP Singh said.
Kumar, a 1973 batch officer of the Indian Police Service, headed the Central Bureau of Investigation from August 2008 to November 2010.
Three years later, he was appointed as the Nagaland governor in March 2013. Kumar was the first CBI chief to be appointed to a gubernatorial office. Later, he was also appointed Manipur till December 2013.
Ashwani Kumar, however, had to step down from the Nagaland Raj Bhavan weeks after the Bharatiya Janata Party (BJP) came to power in the 2014 general elections.
It was during his tenure as the CBI chief that the investigation agency had arrested Union home minister Amit Shah in July 2010 in the Sohrabuddin Sheikh encounter case. Shah was then serving as the BJP general secretary and minister in the Gujarat government led by then Chief Minister Narendra Modi.
Ashwani Kumar began his career as a young IPS officer in Himachal Pradesh where he served as the superintendent of police of Shimla district in 1985. He was also a part of the newly-created Special Protection Group for the security of then Prime Minister Rajiv Gandhi during the same tenure.
He was in the SPG from 1985 to 1990 in various capacities including that of Assistant Director in the Prime Minister's Office.