The Metropolitan Police have launched a joint investigation with the Hammers and the FA in a bid to get to the bottom of what happened.
And Starsport understands the probe could involve some of Van Gaal’s men being interviewed to see if any of them can provide descriptions of who was responsible.
Players who took videos could also be asked to hand over the footage to police, who are already scouring CCTV footage to catch the culprits.
England and United midfielder Jesse Lingard posted a mobile phone video on social media of him and his team-mates hiding on the floor of the coach during the trouble.
Three men were later arrested during the game, including a pitch invader who tried to confront United keeper David De Gea.
Hammers director Karren Brady condemned the “unacceptable behaviour” by a “mindless a few” who would be “dealt with in the strongest way possible.”