Both Tom (who did the initial extensive free evaluation) and Alvin (who did the actual work onsite) were knowledgeable, friendly, and thorough. I gave a long 5-star Yelp review. They found an opening in the roof, near the roof vent, even though the sounds of rodent activity came from lower down. Set the one-way trap (I heard a rodent go out of it), and gradually all sounds in the living room wall ended. The hole in the roof has now been sealed, and one other possible entry point is being addressed. Great work.