Leading features

Leading features
 

-Let me show you the evolution of this case so far as I have been able to follow it. Simple as it has been in its leading features, it has none the less presented surprising difficulties in the way of an arrest. There are gaps in that direction which we have still to fill. =======================
My interpretation:

The case in the beginning looks simple, but when we want to arrest someone as the criminal, we come across diffiulties.

Is it correct?

The main aspects (leading features) of the case are simple, but the circumstances surrounding the arrest are more complicated.

Thank you~

You are quite welcome. :)