Hi Annie and Sylvia,
Personally, I would pay a visit to the British Library and visit their very helpful Oriental and India Office Collections on the 2nd Floor (Readers tickets here are free, after a short interview and photo and card issued). There is also a University of Cambridge Asian Studies section to their Library, though I have to admit I have not yet been near the place, even though I live in the city.
Have no idea how reachable those places are for Sylvia, but I Googled for the British Library and on their integrated catalogue there are 505 hits if you put in "India Police". But I presume these records can only be viewed in London...
When I did the same for University of Cambridge, there were 10000 hits! Right at the top of the list was a book entitled "Police in India" by M.B.Chaude, published in 1997 by Atlantic, New Delhi. Again, this appears not for loan, and one would have go and look at it. Last time, as a non-member of Cambridge University, I had to pay £10 for a 6-month reader's ticket.
I don't suppose this is much help...
Keith