Las Vegas Shooting Co-conspirators

http://www.zerohedge.com/news/2017-10-02/chilling-warning-shooting-attack-you-are-all-going-die

This witness of the Las Vegas shooting reports that a hispanic couple pushed their way to the front of the crowd yelling "everyone is going to die".  This hispanic couple caused such a disturbance that they had to be escorted out by security.  So, what I want to know is, how did these people have foreknowledge of the attack?  Who are they? Also, are there other  witnesses that can corroborate this story? 

The problem with the Las Vegas shooting is motive.  Forensic phycologists have said that young people who conduct unknown mass killings do it for fame.  Older perpetrators kill unknown people for political reasons.   We still don't have a clear motive yet.