Queens Park Rangers defender Anton Ferdinand has reportedly received a death threat over his role in the John Terry race row.
The police were notified after a malicious letter was handed in to staff at QPR last week, according to The Sun.
John Terry is accused of making a racist remark towards Ferdinand during QPR's 1-0 victory over Chelsea at Loftus Road last month.
The Chelsea captain denies the claims, but is facing investigations by both the FA and the Metropolitan Police.
A police spokesman said: "We confirm we are investigating an allegation of malicious communication."
Terry has been named in the England squad to face Spain at Wembley on Saturday, but reports suggest that Frank Lampard may take the captain's armband.
