Nearly 500 police were on duty in and around St. Andrew's and so far they have arrested seven supporters.
But now they are concentrating on rooting out the troublemakers behind the ugly scenes inside the stadium where more than a thousand Blues supporters invaded the pitch, a flare appeared to be thrown into the stands and seats were ripped out.
Supt. Steve Graham told Sky Sports: "The passion we saw 80-85 minutes was exactly what we are proud of within the English game. It is just a shame it spilled over into the criminal behaviour we saw on the pitch at the end."
He added: "There have been seven arrests but that was over the course of the whole operation.
"When the pitch invasion occurred, we were more concerned about asserting some control within the stadium and making sure the crowd dispersed safely and securely.
"We've started a post match inquiry whereby we will seek to identify people who committed criminal offences.
"Sadly we've had some experience of this in the past although it is still an unusual event.
"But we will put steps in place now to identify those offenders, prosecute them and, if they are convicted, they will be banned for along time.
"I wouldn't say we were expecting trouble but we knew it was a strong possibility.
"It has happened in the past, we have got intelligence, and that's why we had the level of officers on duty that we did have."