An investigation has been launched into how excrement was left in Crystal Palace's changing room before their play-off victory over Brighton & Hove Albion this week.
Palace players are believed to have found fecal matter outside the toilets in the away dressing room of Brighton's Amex Stadium, ahead of their 2-0 win in Monday's semi final second leg.
Furious Seagulls manager Gus Poyet, who has since been suspended by the club on an unrelated matter, sent an email to Albion staff calling for someone to lose their job.
The email has since appeared in several national newspapers.
In his email, Poyet said: "When Crystal Palace players and staff arrived to the Amex and went into their dressing room, they found themselves in a very uncomfortable situation, for some reason that still no 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 say it in clear English, someone had a ‘poo’ all outside the toilets, over and around the toilets.
"Now, after careful consideration, and even after a meeting with the Chairman who assured me that MY REPUTATION IS INTACT, I feel that I must express my anger that anyone inside this organisation thought they could interfere with it.
"I am angry that someone within this club could endanger our good reputation and stoop so low - did they imagine that this would affect the Crystal Palace players - well it possible did - it may just have fired them up even more.
"Well 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 changing rooms are high up on securities check lists???
"Surely someone should lose their job to allow such a breach of security - they do not deserve to be part of this club!...
“I am angry that someone within this club could endanger our good reputation and stoop so low.”
Brighton have confirmed an investigation into the incident is underway.
Palace will play Watford in the Championship play-off final at Wembley on Monday May 27.
The winners will be promoted to the Premier League.