A boro fan has been arrested on suspicion of inciting racial hatred after allegedly ripping up pages of the Koran at a match.
And six people have been suspended from attending Middlesbrough Football Club matches as the probe continued.
A 25-year-old man who has been arrested is accused of tearing up pages from the holy text of Islam and throwing them during Boro’s clash against Birmingham City last month.
The fan has been bailed while police continue to investigate the incident.
He is also banned from attending football matches and must not visit any city where Middlesbrough Football Club are playing.
The incident happened during the club’s 2-2 draw, on December 7 at Birmingham’s St Andrew’s ground.
The alleged incident was reported to police by a match steward.
West Midlands Police is investigating the incident and confirmed that a man, from Shrewsbury, has been arrested.
A spokeswoman for the force said: “On December 21 a 25-year-old man from Bicton Heath in Shrewsbury was arrested on suspicion of inciting racial hatred.
“He has since been bailed while the police investigation continues.
“While on bail the man has been banned from attending the St Andrew’s ground, barred from attending any football matches and must not visit any city where Middlesbrough FC are playing.”
After the allegation came to light Middlesbrough Football Club vowed to ban anyone convicted of the crime from the Riverside Stadium for life.