West Midlands Police are investigating allegations of racist behaviour by members of the crowd during the ongoing Test between England and India.
One account on social media said there was racist abuse directed at India fans in the Eric Hollies stand at Edgbaston, on Monday - day four of the Test.
Another account said the "disgusting racism" was "some of the worst abuse we've ever experienced at a match".
Police are encouraging anyone who witnessed abuse to come forward.
A police spokesperson added: "We're liaising with Edgbaston officials to understand what's happened.
"[We] would encourage anyone who heard any racist language or gestures, or has video footage that could help, to get in touch.
"We're aware of images circulating on social media showing an alleged offender. We're making enquiries to identify the person and would urge him to come forward and speak to us."
Edgbaston bosses apologised on Monday and said an investigation was already under way following the allegations on social media. Edgbaston officials said in a tweet: "We're incredible sorry to read this and do not condone this behaviour in any way."
Stuart Cain, chief executive at Edgbaston, said on Tuesday they have spoken to the people who posted to social media, the stewards managing the Eric Hollies stand and the police.
He added: "When this issue was reported to the stewards, they couldn't pinpoint where the alleged abuse was coming from so stewards and the police monitored the area until close of play."
Cain said there was a separate incident reported anonymously to the club via the Edgbaston app, which he said was dealt with "in less than 10 minutes and led to the ejection of three fans".
"For Saturday's Vitality IT20 versus India we will be writing to all fans to remind them of our zero tolerance approach to abuse and also increasing awareness of the app through wristbands, seat stickers, messages on hi-vis jackets and increased speaker and screen messages."
The England and Wales Cricket Board said: "We are very concerned to hear reports of racist abuse at today's Test match.
"We are in contact with colleagues at Edgbaston who will investigate. There is no place for racism in cricket."
Later on Monday, Stuart Cain, chief executive at Edgbaston, added: "I'm gutted by these reports as we're working hard to make Edgbaston a safe, welcoming environment for all.
"Having seen the initial tweets, I've spoken personally to the gentleman who raised them and we're now speaking to the stewards in this area to establish what happened.
"Nobody should be subject to any form of abuse at Edgbaston. So, once we've got all the facts, we will make sure this issue is addressed swiftly."
An India fan identifying herself as Reena said: "Had an amazing three days watching Test cricket with some brilliant fans from both teams but today ruined the whole experience.
"Waited a long time for this Test match, what a sad ending."
England need 119 more runs to beat India on the final day.