A fun and enjoyable read
I just finished this a few days ago and can heartily recommened this to anyone who likes mysteries the way they used to be written in the '30s -- there's lots of action and a orang utang (spelling?) named Bhag who also fronts as a kind of butler.
There's a lot of good fun in this mystery and a lot of good characterization.
If you haven't yet read this, I think this would be a good example of Edgar Wallace's thrillers from the '30s.