No, they have physical evidence, audio evidence which probably means camera or video doorbell and the kid died on the front porch of someone else's house. Seems like the story told itself. The simple explanation is he tried breaking into the wrong house thinking it was his own.
Not saying he deserved to die over his mistake, it's tragic and sad that the situation occurred.
Editing to add this from the article:
"evidence gathered at the scene, review of surveillance video that captures moments before the shooting, audio evidence, and witness statements."
It doesn't have to be some privacy focused security super encrypted email service if that doesn't fit your use case. Use outlook.com, fastmail, proton, try one out for just shopping accounts that you check for orders and shipping etc. I get that we should have privacy and outlook isn't any better than gmail but I'm just not an all or nothing kinda person. If you're cool with what it offers and what it takes, then try it out.
Note that I use proton, paid member for 4 years and going. Happy with service. My point is that you need to pick the right tool for the job.
My choices are more about not having everything on Google (or being let down yet again) than my fear of google knowing I emailed my accountant two months ago or that I bought a dog poop scooper from Amazon.