A 15-year-old boy from Blackburn was interviewed by Lancashire Police in connection to an alleged racist incident involving Philippines goal-keeper Neil Etheridge.
Etheridge reported an incident of racism during Birmingham City's FA Cup match against Blackburn Rovers last week. He addressed the issue to referee Keith Stroud towards the end of their match.
Birmingham have given their full backing to Etheridge.
In a statement on Saturday, the Club said that they "welcome the findings of Lancashire Police after Neil Etheridge reported an incident of racism during the Emirates FA Cup tie against Blackburn Rovers on Saturday 28 January."
"On Thursday 2 February, a 15-year-old boy from Blackburn was interviewed under caution on suspicion of a racially-aggravated public order offence," they added.
"The matter will now be referred to the Youth Offending team who will decide on the appropriate action to take."
"Blues will continue to give its full support to Neil in any way it can and reiterates its position that there is no room for racism in the game."
Etheridge has said that he is "proud of what I did to bring to light, once again, an ongoing problem that we all have a responsibility to tackle head on."
"Racism and all forms of discrimination should not be tolerated," he added. "We cannot eradicate it overnight, but if we can all keep doing our bit to educate those out there, I hope and pray that my child, and our children, can grow up in a better world."