Were the walls that were being remodeled in the basement torn out following the murder? I'm asking because it would have been simple enough to drop the missing portion of the paint brush into one of those holes in the walls.
I don't think the Rs were doing any basement remodeling. I think they might have had some electrical or other work done at some point, and the basement was left that way.
The house was sold very soon after JB's funeral to a group of R "friends and investors", who did not remodel, but they did pull up all the carpets and remove all the wallpaper and they painted all the walls white. They pretty much obliterated any chance there was of trying to find any forensic evidence (urine stains on the carpets, blood splatters, etc".
Then, the house was sold again ( I think twice more, actually) and completely remodeled. The last people who bought it have had it for sale for a few years now. They completely redid the whole house- and they did a great job. Beautiful new kitchen, new baths, and the basement is a gorgeous huge family room complete with fireplace. They walled up the wineceller. I think they may have built a REAL wine room, too. The pictures were available when the house was for sale- it may still be for sale, so the photos may still be there.
One of the previous owners asked to have the address changed because the house was the target of vandalism as well as numerous sightseers and curiosity seekers. The address WAS changed, but the house is so distinctive that anyone who knows even a little about the case knows which house it is, even with a new address. Hard to miss a pretty brick Tudor with a hideous modern monstrosity stuck on the back of it.