West Ham are investigating the reason behind West Brom's Jake Livermore confrontation with a fan at the London Stadium amid suspicions it may relate to the death of the midfielder's son, reports BBC Sport.
The England midfielder became involved in an angry exchange with a fan after he was substituted in the second half of his side's 2-1 defeat.
Livermore and his partner lost their newborn son Jake Junior in May 2014.
Neither club has commented about the precise reasons behind the incident.