BBM. Strangely, it appears that the above Tweeet has been deleted, and I haven't been able to find a copy of the arrest warrant.
I am sorry if this has already been pointed out, and/or if the screenshot I am going to try to attach here is not allowed (mods, please snip/delete, if not permitted). Alternatively, here is the link (which I do believe is allowed): https://www.instagram.com/p/-pcJ2gtrUM/?taken-by=nicky_maddie_lovell_15114
I know we haven't agreed as to whether the "David A" here is in fact David Eisenhauer, but I believe that it is (besides, AP reported that the mother of Nicole's 8-year-old neighbors told them "her daughters told her that the seventh-grader had showed them a picture of "David," along with a thread of texts they had shared using the Kik Messenger app on her phone.").
Nicole posted this to Instagram nine weeks ago (or November 28th to be exact; this shows up if you hover the mouse over the "9w"), and it shows that "David A." had texted her the previous Friday, which would have been November 27th.
I am so glad that Ms. Snider, the neighbor, spoke up. Without the tip, I suspect it would have taken LE quite a bit longer to connect the dots.
It appears his message was "lg". From internet slang sites, that's "little girl."