NOTE: If you have a week stomack or can't handle sex talk you may not want to read what Sam has to say.

According to everything I've read and know. The tapered end of the paint brush was used to insert in JB virgina by evidence of varnish and splinters BUSTED HYMAN..
I think the perp was performing cunnylingus to her as he pulled out and inserted the end of the paint brush.
He was trying to get JB to reach a super orgasim.
He had to pull her panties down at least far enough so he could insert the end of the paint brush into her virgina.
That's far enough to perform cunnylingus and leave (saliva) dna.
Then he is pulling on the garrott suffocateing JB so he can get the andorphines (sp) flowing in order for her to have that super orgasim.
In the killers mind that's probably when she revealed herself to him.
He cracked her in the head with a blunt force object. Took the end of the paint brush for a souvenire and his tools ( tape,rope and stun gun).
Made his get away through the basement window.
THAT'S WHAT I WOULD DO !!!!!!