True, my info comes from the major media so who knows if trustworthy - but my understanding is that the female Asian victim is the daughter of a fellow cop that the killer has sworn a personal vendetta against. And the black man being her fiancee, he’s like family, too. IOW, he killed them because of a sworn vendetta against her father.
The manifesto is up on Drudge. He calls out Whites, Blacks, Asians, Latinos, and lesbians as high value targets. He is deranged, but his killings are not racially motivated.