Sorry this is long. Just some things I'm mulling over, and it's nothing new and groundbreaking, but based on some discussions here as well as looking at the case on other platforms I'd say im leaning torwards:
1) perp began by kicking at the door. James and Denise both heard some sort of noise at the front of the house and James went to investigate and found it was coming from the door. Once he realized it was someone or more than one person trying to get in he yelled for Denise to hide and call 911. By this time the perp had been working on the door so he finally got it down before James had a chance to hide anywhere himself and was shot immediately- hence why initial report was that the man down had "answered the door"
Denise was in the process of calling 911 but was shot in that limbo area of phone calls where it takes a second after you dial for it to hook up and start ringing to the number you're calling. This would account for dispatcher not being able to speak with anyone but hearing commotion and jayme's "help!" in the background
2) someone forcing their way in makes some people think burglary, but perp seemed ready and prepared to kill whoever was at the door. Could still possibly indicate burglary but from what I've seen and have been told by cops, most home burglars want to take the path of least resistance when they break in. They don't want to make a lot of commotion and draw attention, and they typically don't want to bring murder into it--yes they probably aren't of the highest moral fiber but really, they're there for money/goods. I know people who have been home when a burglar came in and perp didn't kill them--they were too busy tearing the house apart. They want to get in and out as quickly as possible (one caveat to this is that if perp was high, the typical home invasion scenario very well may not apply here and they could come in a blitz attack and not be worried about being inconspicuous.) but I'm really thinking this wasn't a burglary motive. They either wanted James/Denise dead from the get go for a personal vendetta against them, or they wanted them dead in order to take Jayme. So I guess now I'm still leaning away from this being totally random
3) there's been a lot of talk about burner phones and apps where teens can be secretive. I have nothing to add on that front but I will say that I was a teenager in the late 90s into early 00s when the internet was really taking off and quite the novelty. I was like Jayme in a lot of ways- shy, but friendly and smiley, and not overly mature for my age. I talked to A LOT of boys in chat rooms and over instant messenger. I exchanged pictures with them, even talked to some of them on the phone. My parents didn't really know the extent to what I was doing. However, at least my best friend knew if not a couple friends. They were doing the same thing, some more than others. When you're 13 you're really starting to move your friendships away from just child's play into confiding and discussing teenage hood topics like wearing bras and shaving and periods, boys, teachers, etc. Teenage girls talk A LOT. If Jayme had been talking to a male, I really believe LE would know that from interviewing her friends.
Just my experience and JMO