I do believe you have hit upon a new and subtle method of assassination.

Gradually, the original efforts were replaced by more subtle methods.

It typically involves subtle methods of coercion such as intimidation.

It's likely that Aristotle would have created far more subtle methods of manipulation.

He must work by a more subtle method.

We Arabs are noted for the more subtle methods of gaining obedience.

"Do you not yet understand the subtle methods of our survival?"

But he would use subtle methods to reach his goals.

He preferred more subtle methods of delivering death to helpless victims.

Failing this, there is a subtler and more entertaining method.