West Ham have identified the supporter who was confronted by West Brom midfielder Jake Livermore during Tuesday’s Premier League match.
The fan is understood to have shouted to Livermore, and an investigation is under way to establish whether he directed abuse about Livermore’s baby son, who died in 2014.
England international Livermore, who was substituted just after the hour, had to be escorted down the tunnel following the incident, which was not clearly picked up on CCTV footage.
West Ham acted quickly to eject the fan, who was spoken to by stadium staff on Tuesday evening.
Press Association Sport understands the London club are continuing to actively look into the matter, working with West Brom and 28-year-old Livermore to determine exactly what happened.
The 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 Livermore are expected to make a statement later on Wednesday.
Baggies boss Alan Pardew said after his team’s 2-1 defeat that he had seen Livermore among supporters in the crowd, but did not know what had provoked the midfielder’s 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,” Pardew said.
“There’s no way he’s going in the crowd – because I know him, he’s a great lad – unless he was provoked severely. That’s all I know.
“I haven’t had a chance to talk to Jake. I’ll speak to Jake and we’ll go from there.”