Durham Police have reportedly issued a warning to the ex-boyfriend of Adam Johnson's sister after he allegedly harassed the footballer's teenage victim on social media.
According to The Guardian, Mr Knox, who is the former partner of Faye Johnson, claimed on social media that the schoolgirl "bragged and lied".
Police have now issued a harassment warning to the individual for causing a "considerable deal of distress and harassment" to the victim.
Johnson, who was sacked by Sunderland last month, was convicted of one count of sexual activity but was cleared of another charge relating to oral sex.
Before the trial began, the footballer admitted to kissing the 15-year-old girl when the pair met in his parked car last January, as well as grooming.
Johnson will be sentenced on Thursday.