Unfortunately, you've just answered your own question. They have undercover spotters all over the away end at Anfield waiting for the moment and yes, those arrested and charged will have video evidence against them. I just posted this in the United thread regarding my mate who got lifted there last season, but it also belongs here as well. They laughably wanted to give him a 3 year Football Banning Order - you know, where you have to surrender your passport on match days, etc, and all that bollocks - which is usually only reserved for top shelf football hooligans. He paid a fair whack for a decent solicitor and got a lot of the case including the application for the 3 year FBO thrown out due to inconsistencies in the process as they tried to add bits on that weren't true but what he couldn't change and couldn't deny was that they had video evidence of him singing "Murderers":
What I would add is that I don't believe chanting "Murderers" in relation to Heysel should ever be classed as a tragedy chant because, if anything, it's a reverse tragedy chant due to it not mocking those who died but those fans who perpetrated it. If people were mocking the Hillsborough or Munich dead then that's different of course but it's obvious that Miseryside Police now have a zero tolerance approach to anyone who dares remind Liverpool fans of what cunts they were at Heysel, whereas no doubt they turn a blind eye to any fucker on the Kop glorifying the amount of Mancunians that Harold Shipman murdered. After what happened to my mate there last season who got lifted for chanting "Murderers" - and who has now been banned for 3 years by City even though his lawyer drove a coach and horses through much of the prosecution's case meaning the authorities never imposed a 3 year FBO on him - I had to quietly warn a couple of ours in the away end this season that there are undercover spotters all over that end just waiting to pounce on any fan who utters that word.