Brighton and Hove Albion have formally apologised to rivals Crystal Palace after excrement was reportedly found on the floor of the London club's changing room prior to the second leg of their Championship play-off semi-final last week.
In an email sent to Brighton's season ticket-holders late on Monday, chief executive Paul Barber pledged to tighten security at the club's Amex Stadium.
"We apologised to Crystal Palace as soon as the vandalism in their dressing room was discovered, and again more formally a few days after the match," he said.
"As a result of what happened, please rest assured we have reviewed our internal procedures to guard against this ever happening again."
In a matter apparently unrelated to the changing-room incident, Brighton manager Gus Poyet, assistant Mauricio Taricco and first-team coach Charlie Oatway were all suspended pending investigation after the 2-0 loss to Palace, but Barber refused to discuss the issue.
"On other matters, you will appreciate that I'm unable to comment further at this time," he said.
British media reports on Tuesday claimed that Poyet sent an angry email to club staff demanding to know who was responsible for the vandalism in the Palace changing room.
In a transcript published on the Daily Telegraph website, Poyet was alleged to have said: "When Palace players and staff went into their dressing room they found themselves in a very uncomfortable situation.
"For some reason which is still no (sic) clear to me, someone during the day had access to the away dressing room and done something terrible trying to upset everyone related to Palace, to put it in clear English, someone had a "poo" all outside the toilets, over and around the toilets."
He added: "Someone made a very bad decision and I think it is time to stand up and take responsibility -- not just the culprit but those employees who are supposed to make our stadium safe and secure.
"Surely someone should lose their job to allow such a breach of security? They do not deserve to be part of this club."
Palace are due to face Watford in the Championship play-off final on Monday.