I agree, as far as usual MO goes. This one looks like a revenge act against police, and given the recent news, the revenge would be coming from "elements in the black community." But, if I was a thinking person in ISIS, and wanted to hide my motive, I'd do attacks that naturally attached to other elements of the society I am trying to disrupt.
Occam's razor says BLM revenge.
ISIS made an announcement after the homo slaughter, that jihadis should kill white people to make sure people knew they weren’t just “hate crimes”.
And ISIS has been teamed up with BLM since Fergesun. Also Palestinians were there giving training in street violence.
There’s a lot of black Muslims, not necessarily ISIS.