Nathan Thompson spoke to referee Jarred Gillett following the alleged incident
Birmingham say no action has been taken against two fans who were arrested after an allegation of racist abuse during their match at Peterborough.
Peterborough centre-back Nathan Thompson made a complaint to referee Jarred Gillett during their Championship game on 18 September.
Cambridgeshire Police have confirmed that no further action will be taken against the two Blues supporters.
Peterborough won the match 3-0 at the Weston Homes Stadium.
Source: bbc.com