South Yorkshire Police are investing an assault on Sheffield Wednesday goalkeeper Chris Kirkland by a fan during the Yorkshire derby with Leeds United.
Michael Tonge's equaliser for visitors Leeds saw a fan in the away section run from behind Kirkland’s goal and push him to the ground.
Approaching from Kirkland’s left, the thug ran up to him and caught him unawares with a double-fisted blow that floored Sheffield Wednesday keeper.
South Yorkshire Police issued a statement on Saturday morning which indicated they know the identity of the individual involved, who ran back into the stand after the assault and escaped arrest.
Senior Investigating Officer Detective Inspector Mark Monteiro said: 'With the public's assistance we have clearly identified the offender who ran onto the pitch during last night's game between Sheffield Wednesday and Leeds United and who is suspected of assaulting the Sheffield Wednesday goalkeeper.
'We are dealing with the complaint made by the player and are currently taking statements, collating evidence and making enquiries to locate and arrest the offender.
'We are also using CCTV footage from around the ground to identify suspects who may have been responsible for other offences before, during or after the match.'
The suspect was widely named on social media sites last night, and if it proves to be him, he has previous convictions for football-related violence, and is currently serving a nationwide ban on visiting any football stadium in the country.
Leeds manager Neil Warnock was furious after the match and said he was 'absolutely embarrassed' by the incident. 'I thought it was an absolute disgrace,' he said. 'I think they should get the guy and prosecute him and put him in prison
'He (Kirkland) went down like a ton of bricks but that doesn't make a difference. Nobody should be on the pitch doing that. I hope we can make an absolute issue of it. He spoiled everything for everyone. I've not enjoyed that when I see a moron like that.
'I am not proud of being Leeds manager when I see that. I don't mind the rivalry between us - there was a great atmosphere. To see things like that on the field of play there is no place for it - I am absolutely embarrassed.'
He continued: 'They had enough security.
'If they have got a person like him with a five-year-old mentality they can't stop that. Sheffield Wednesday can't do anything about. It just gives them more opportunity to have a go.
'Dave (Jones, Wednesday manager) was saying we shouldn't thank the crowd but our crowd were fantastic but we've got one moron and I can't tolerate that.
'I've not seen anything like that since my mate Paul Evans got something thrown at him at Burton Albion in an FA Cup game many, many years ago. All of them apart from one moron were excellent tonight.'
Furious Wednesday boss Jones described the Leeds fans as: ‘Vile animals... an absolute disgrace,’ and said they should be banned from every away ground.
There were offensive chants from both fans during the game, about Jimmy Saville from travelling Leeds fans, with Sheffield Wednesday supporters singing songs that referenced the two Leeds fans who were killed in Turkey in 2000.
Minutes after the full-time whistle, Leeds United released a statement promising to work with the police to identify the man responsible for the sickening attack.
South Yorkshire Police have confirmed in a statement they 'will be working with both clubs to identify and quickly bring to justice the persons responsible'.
In his post-match press conference, Warnock stood by his club's statement and called on the culprit to be jailed.
'It's just so sad and disappointing. If anything it stopped us winning the game. I thought at 1-1 we would get in the driving seat and that made everyone... for one moron,' he said.
'The club has made a statement and I'm pleased, we don't condone that. I hope the authorities and constabulary take the appropriate action.'
A spokesman for Leeds United said: 'Leeds would like to apologise and condemn the actions of the fan who came into the pitch and attacked Chris Kirkland. The club will fully cooperate with both the police and the football authorities in identifying the individual concerned.'
Having sensed a tense atmosphere in the first half, Warnock also claimed to have asked police if they wanted him to address Leeds' fans in order to calm tempers.
'There were some early on, they (the fans) went towards each other, the police said they didn't think it would be right. It looked to me.... I was disappointed in certain aspects of being manager tonight when things like that happen,' he said.
'I did say to the police, in the first half, did they want me to go over and calm them down but they said that might inflame it even more.'
He did not agree with Jones' assessment that he was in the wrong to send his players to clap the travelling fans, though.
He said: 'I disagree, Dave is disappointed with not winning the game. I understand his feelings being a manager, it's a pressure game, he felt they could have won it.
'Leeds United coming was the best thing that could have happened to him, if it was a lesser team coming, on the run that they're on, it would have been very difficult, but the crowd lifted them.'
This incident will be an embarrassment for the FA as it comes three days after their complaint about the unruly and racist behaviour of Serbian fans, players and officials after England’s Under 21 victory.
As Kirkland lay flat out on his goalline, seats that had been ripped out at the away end rained down on to the Wednesday six-yard area. As the assailant clambered back over the barriers and reclaimed his seat, team-mates and physios rushed to Kirkland’s aid.
When he finally climbed to his feet and signalled he was able to continue, he turned to the travelling fans and pointed an angry finger towards them.
Tension between rival supporters had threatened to boil over minutes earlier, but a flashpoint that involved a shameful physical attack on a player is sure to land Leeds in trouble with the authorities, who will launch an immediate enquiry into it.
Jay Bothroyd had already made it an uncomfortable return to his native Sheffield for Neil Warnock.
Bothroyd, a deadline-day loan signing from one-time Sheffield United boss Warnock’s former club QPR, steered a 44th-minute header past Paddy Kenny’s despairing dive to give Wednesday a deserved lead.
Wednesday boss Jones bemoaned his side’s recent misfortune in his programme notes, and he had more grounds for complaint as Wednesday dominated the first-half. Third from bottom at the outset, Wednesday belied their lowly position with some fluent passing that lacked only a finishing touch.
How it went unrewarded for so long took some explaining, though, after a remarkable 10th-minute escape for ex-Sheffield United keeper Paddy Kenny and a glaring blunder by referee Eddie Ilderton.
Bothroyd’s 30-yard shot almost embarrassed Kenny but the crossbar came to his rescue after he spilled the striker’s strike. As Wednesday continued to press, they were denied a clear penalty when Luciano Becchio dived full-length and palmed away a Bothroyd corner with his right hand.
Bothroyd finally made Wednesday pressure pay, following a 44th-minute long throw from Michail Antonio. The striker rose highest, and though his header lacked venom, it was directed well enough to defeat Kenny’s dive.
As he celebrated the breakthrough, Bothroyd appeared to be struck by a missile from the Leeds end. It was not the only unsavoury note of a first half that often threatened to boil over.
Michael Brown was guilty of overreacting after Miguel llera barged into him on the edge of the area. The Leeds midfielder went down clutching his face, despite contact appearing to be with his shoulder.
Ilderton took no action, but may well have punished Llera for another flashpoint, when the central defender floored Becchio with what looked like a forearm smash.
El Hadji Diouf was being barracked more than any of the former Sheffield United players on view, and he duly played up to the role of villain in a running verbal battle with Ilderton over a series of decisions.
But for all the aggression shown on the pitch it is the actions of one crazed individual which will occupy the football authorities as they investigate the end to a troubling week.