Liverpool will impose a lifetime ban on any supporter found to have racially insulted the Oldham Athletic defender Tom Adeyemi. The club have been investigating an incident at Anfield with Merseyside police, who said on Saturday night they had arrested a 20-year-old Aintree man on suspicion of a racially aggravated public order offence.

The man was being questioned by officers after Adeyemi was reduced to tears in the 80th minute of Oldham's 5–1 defeat in the FA Cup on Friday. Liverpool, who have come in for fierce criticism over their handling of Luis Suárez's eight-match ban for racially abusing Patrice Evra, have been swift to act after Adeyemi's alleged confrontation with a fan at the front of the Kop.

Liverpool said in a statement on Saturday night: "Liverpool Football Club continue to work closely with Merseyside police to establish all the facts surrounding the incident that occurred during last night's game. We take this matter extremely seriously and have today provided the police with the evidence we have available to us. This includes CCTV coverage and still photography of what we believe to be the relevant part of the stadium, statements from matchday stewards in that area and full access to all the footage captured by the cameras filming the match for our in-house TV operation.

"In addition, we have examined records of the tickets purchased in that part of the ground to see if they provide any additional information and have passed that on to the police. Finally, we would also urge any of our supporters who witnessed this incident or saw the individual involved and who have not already done so, to contact either the club or the police."

Adeyemi is understood to have told police that he was racially abused twice by a supporter and witnesses have backed this up, telling the police that one of the terms used was "You fucking black bastard". Other supporters who claim to have been close to the incident have alleged that the phrase was "You fucking Manc bastard".

Audio recordings from the Kop end of the pitch could form part of the investigation. The Football Association have yet to become involved but are expected to do so once the referee Neil Swarbrick's match report is submitted on Monday.

Liverpool's statement came after Piara Powar, executive director of European football's anti-discrimination body Fare, criticised the club. "The obvious thing for LFC today must be to come out as a club – owner, manager, captain – and start to undo some of the damage, including addressing their fans," he wrote on Twitter. "Go onto the LFC website and there is not a single expression of regret about what happened last night.

"Are LFC fans going to do this at every game, support the mistakes made by their own man [Suárez] by abusing others? 25% of PL players are black. That's a lot of players to abuse. Top clubs have unprecedented influence and power over millions of people. They should exercise that power responsibly, if they don't it's time for the authorities to step in."

The Oldham captain, Dean Furman, branded Adeyemi's treatment at Anfield "an absolute disgrace" but declined to comment on whether he had been told the abuse was of a racial nature.

Furman, who helped calm the young right-back after the incident, told the BBC: "He was abused and I'll leave it to Tom and the police to investigate that. What happened should not happen in the game. It has been highlighted over the last few months and it is an absolute disgrace."

When pressed on whether Adeyemi's allegation had been relayed to Oldham's players, Furman responded: "It is difficult for me to say anything. When one of your boys is down like that we all feel it. Tom, the authorities and police will sort out the situation. I hope the authorities take heavy action because it was a disgrace. A lot of credit goes to Tom for the way he handled the situation."

Adeyemi's former team-mate Rueben Hazell has stated on Twitter that the abuse the 20-year-old received was racist. Hazell wrote: "After the game I went into the Oldham dressing room to catch up with my old mates and spoke to Tom Adeyemi directly about what the altercation with the fan was all about. He said he was racially abused by the fan. This is FACT. He also said that police want to speak to him and was asking 4 advise (sic) from his team-mates what to do. Every1 around him told him 2 go ahead and give his version of events to the police.

"It's time for this kind of behaviour to stop. This isn't acceptable in football or in society and its time 4 black players 2 show a stand like young Tom did. As a 20yr old I thought he managed the situation extremely well and it was sad that the incident reduce him 2 tears in what should of been the happiest day of his footballing career to date."