Also, the media has excellent sources in the FBI and other LEO organizations.
Yet nothing about the political motive they are pursuing has been leaked. Only stuff about bump stocks and assault rifles.
So one would guess whatever it is, the motive is not something advantageous to the MSM agenda or at least some of these aggressive, ambitious and soulless media types would have leaked something about it.
They may try to just keep it under wraps permanently citing “national security” or some other excuse.
IMHO LE is finding other people. That’s why they are saying nothing about motive, other than the broad hint to those who pay attention that “he may have been radicalized and we are looking into how”.