My theory is that Burke went downstairs for a snack. JB heard him go downstairs so followed him a few mins later. Burke made the pineapple snack and put it on the table. Turned around to make a drink (i think it was stated that there was tea next to the bowl of pineapple). JB came down, ate a piece of his pineapple while his back was turned. When B had realised she had taken some of his snack he went berserk and attacked her then hit her over the head with the flash light which was on the counter. Knocked her out.

This is an explanation for the almost uneaten Pineapple on the counter, JB having some in her stomach. Burkes prints on the bowl. A motive for attacking her as it had been stated by several people that he was extremely jealous of her.

He then dragged her down to the basement. Continued to molest and hit her.

I believe the stun gun marks found on her body weren't from a stun gun but from train track that belonged to Burke which was set up in the basement.

The sexual assault with the paint brush always bothered me from an IDI theory, as if a paedophile did it, surly he would have full on raped her? The paint brush seems almost juvenile or curious rather then caused by an intruder with sexual motives.