Meta had taken down an Instagram account after a Championship footballer was subjected to racist abuse.
Luton Town FC said their forward Elijah Adebayo received the racially abusive message after their 2-1 defeat by Sunderland on Wednesday.
It's not the first occasion that Luton have condemned racist comments made online to the 26-year-old, who last year said he was "fed up" of the abuse he received.
Meta confirmed that it was in touch with the club, who also reported the incident to police.
"Is It Ever Going to Stop?"
"We're angry, upset and frustrated to report that racist abuse has been directed towards Elijah Adebayo," read the statement on the club's website.
"To the person who cowardly trolled into Elijah's DMs: We know who you are, and you know who you are. You're not some anonymous account, one which we've sad to become so accustomed to reporting in recent years.
"Just as we said a year ago, and just as we will do WHATEVER a player or staff member is subjected to abuse, we'll stand by and support Elijah without question."
Luton Town FC said its footballers Jacob Brown and Mads Anderson had recently visited Ferrars Junior School for an anti-discrimination workshop. It also previously joined the Premier League's No Room for Racism campaign.
"We are all Luton and we will continue to support and champion these initiatives until such time that the message gets through to the ignorant minority,\\" the club added.