California Literary Review has a short and insightful interview with Michael Behe about his latest book and among other things asked him what evidence there is of a designer.
Behe explains in part:

Whenever we perceive a “purposeful arrangement of parts” we suspect design. The more parts there are, and the more clearly they fit the purpose, the more confident our conclusion of design becomes. In the past fifty years science has discovered a very purposeful arrangement of parts in the cell’s molecular machinery. That is the evidence for the involvement of a designer in life on earth.

You can read the full interview here.