Premier League stars are ignoring advice to report online racial abuse amid fears of provoking further attacks.
Sportsmail revealed last week that clubs have told all victims to inform the police of incidents as part of a zero-tolerance approach.
But several players, three known to Sportsmail, have been unwilling to do so, leading to concerns that offences will go unpunished. Two of the three have been abused by the same account.
On Monday, the Metropolitan Police confirmed the arrest of a 21-year-old following hateful messages posted over a number of months, while a 49-year-old was arrested last month in connection with the online attacks on West Bromwich Albion's Romaine Sawyers.