Even when police are tight-lipped we usually get a reasonably good idea of motive because the media interviews the suspect's friends and family, finds deleted social media posts, get the person's work and school history which is publically available. None of that seems to have been done here. I suspect that is because the suspect is black. When the story first broke it screamed hate crime. That is why we heard about it in the first place. When it emerged the suspect is black the story was no longer 'sexy". Another important reason the story is not "sexy" is that nobody got hurt or killed, and no damage was done. She was prevented from lighting the gasoline she poured on the porch.
_________________
“Self Acceptance is a process not a performance”
“You are autistic enough. And you always have been”
Professionally Identified and joined WP August 26, 2013
DSM 5: Autism Spectrum Disorder, DSM IV: Aspergers Moderate Severity.