Seriously, Fres, someone earlier asked HOW could someone sneak in while DAMON was in the house, and get to Danielle.
If you will remember back when this started (I have been following these threads since the very beginning) there was rumor or information that DAMON was off DOING a female friend during the time he was supposed to be home babysitting ! Everyone has forgotten this detail. Maybe because it was unfounded, or unproven. Doesn't mean it was necessarily UNTRUE.
If he wasn't there, WHO could have entered the home (or known which door to enter) without alarming the children ?????? Someone they KNEW well. Someone they trusted. Someone whose wife was away, someone that had a date with Brenda, only to find she is with others, doing others in the parking lot, being bought drinks by DW. Maybe he thought DW was moving in on Brenda. HOW TO GET DW out of the picture and have a little fun at the same time ???????? Seems obvious to me.
It's called MOTIVE and OPPORTUNITY ! ! ! ! ! !