The original audience is now older, many living outside India (in the US, UK, or Middle East). Importing a physical book from Kolkata is expensive and cumbersome. A PDF is instant and free.
The good news is that you do not need to risk a virus or legal trouble to read Madhubabu. Thanks to the digital revolution in Indian publishing, many of his classics are available again.
A Kiriti Roy mystery where the detective solves a locked-room murder.