London - The West Ham United fan who provoked West Bromwich Albion midfielder Jake Livermore into climbing into the crowd during his side's 2-1 defeat on Tuesday has been identified by the London club.
The fan was ejected soon after the incident whilst Livermore, who had just been substituted, had to be escorted down the tunnel.
Sky Sports News have reported that the altercation followed remarks made about the England midfielder's baby son, who died in 2014.
The English Football Association has also requested observations from all parties on the incident.
Once the investigations are concluded, West Ham intend to take swift action regarding the individual concerned, with a stadium ban being considered.
West Brom and 28-year-old Livermore are expected to make a statement later on Wednesday.
Albion boss Alan Pardew admitted he saw Livermore among the crowd at the London Stadium but did not know what had happened to prompt his actions.
"The only thing I know is I see Jake in the crowd, which disturbed me. Obviously you don't want to see a player in the crowd.
"There's no way he's going in the crowd - because I know him, he's a great lad - unless he was provoked severely."