I had read earlier that Danielle's bedroom was on the second floor. Also, the family had a large, though "debarked" dog. Now a dog does not need to bark to jump on or bite someone if the dog is startled by an intruder. So, this means that if it were a random intruder, they would have had to entered the house at a time when the mother was out, the dad was napping, get to a second floor bedroom, and get past a large dog.
While anything is possible, it is more plausible, that it was someone familiar with the family.
Is it typical to debark a dog? I'm not a dog owner and I have never heard of this.
Either the intruder knew the dog or perhaps the dog was involved in the Garage Party.