Niladri Sarkar or Colonel Niladri Sarkar is a fictional detective character created by Bengali novelist Syed Mustafa Siraj.^[1][2] Some of the Colonel stories written for children were translated into English.^[3]

Niladri Sarkar is a retired Colonel of the Indian Army, jovial and looking like Santa Claus. He introduces himself as a nature specialist, butterfly collector and ornithologist.^[4] The Colonel smokes a pipe and is fond of Coffee. Most of the Colonel stories are narrated by Jayanta Chowdhury, a reporter of Dainik Satyasebak Patrika. Jayanta is a lazy journalist who accompanies him on his missions. Sometimes Mr. K. K. Halder, a bit eccentric retired police officer also joins with colonel Sarkar. Colonel likes quoting Bengali proverbs and nursery rhymes. He maintains a good temperament while solving mystery. Colonel solves complex cases in his own ingenious way.^[5][6]

The first story of Colonel Niladri Sarkar 'Chaya Pore' was published serially in Amrit Magazine in 1970. Thereafter Siraj wrote hundreds of stories for teen and adults.^[7] Some of are:

In 2013 a film Colonel was released under the direction of Raja Sen.^[8] Chiranjeet played the titular role and Saheb Chatterjee played as Jayanta.^[9][10]