He is the creator of the detective character "Goenda Colonel", the Detective Colonel. Ex-Colonel Niladri Sarkar is the hero who finds the culprit or killer. The stories are very popular earning Siraj a dedicated fan following. From children to old people, there are huge number of readers who are fond of Colonel Niladri Sarkar. A retired Colonel – Niladri Sarkar – is the eccentric sleuth in Syed Mustafa Siraj's stories, narrated by a lazy journalist of "Dainik Satyasebak Patrika", Jayanta, who accompanies him on his missions. Sometimes Mr. K.K. Halder, retired police officer also accompanied the colonel Sarkar. The colonel is a butterfly collector and ornithologist, smokes pipes and has a Santa beard. He is also jovial and likes quoting Bengali proverbs & nursery rhymes. The Blogus blog displays first-published illustrations from the first Colonel Niladri Sarkar novel "Chhaaya Pawrey".