Who is M. Das from Song of Kali and what is their importance?

M. Das is India's most renowned poet in the mid-20th century, Das disappears after his father's funeral in July of 1969, during the Festival of Shiva. Family and colleagues presume that he is dead and mourn him greatly. Calcutta Metropolitan Police Inspector Yashwan Singh, however keeps the official case open and continues for eight years to look for clues.