Fulham were relegated because they removed a statue of Michael Jackson from Craven Cottage, according to former owner Mohamed Al Fayed.
Fulham were relegated at the weekend and the statue has been donated to the National Football Museum in Manchester.
"When the new owner decided to move it I said 'Fine, it is a lucky thing, you will regret it later'," Al Fayed said.
"Now the new owner will regret it because I warned him. I said 'You will pay with blood for that' because it was something loved by people.
"It was a big mistake but he paid for it now. He's been relegated and if he wakes up he'll ask for Michael Jackson again and I'll say 'No way'."
Al Fayed believes manager Felix Magath is not the right man to get Fulham promoted from the Championship.
The Cottagers were relegated after 13 years in the Premier League with Saturday's 4-1 defeat at Stoke.
Magath wants to stay on but Al Fayed does not believe the German can help the Cottagers bounce back.
"You need a manager who will deliver and I don't think this guy has got the charm or the personality," he said.
Al Fayed, who sold Fulham to Khan in July last year, added: "Players need someone very close. You saw me with the players in the changing room and when they're eating lunch, it was a very close relationship for the players to feel they want to sacrifice, play hard and want to deliver.
"They miss that now and I hope [Khan] wakes up. I tried to help him and advise him and put him on the right way.
"If he's lost hope and he offers it to me half price, fine I'm going to buy it back."
Magath has apologised for the defeat at the Britannia Stadium that sealed the club's relegation from the Premier League.
The former Bayern Munich boss, 60, joined Fulham in February, but picked up just three wins in 11 league games.
In an open letter to fans, Magath also vowed to stay on as manager and build a team able to return to the top flight.
"We as a team, and I include myself and management, would like to apologise for our bad performance," the German wrote.
"The reality is that we have been relegated, but my commitment and desire to Fulham remains.
"It certainly was not what you as fans were expecting and should rightfully demand of us, but we were unable to perform on the day, resulting in our downfall.
"During the summer months there most certainly will be many changes within the club. We obviously need to improve and redefine our playing staff. We have in our academy team, talented, young and hungry players."
Fulham's final game in the Premier League this season is a dead rubber against Crystal Palace at Craven Cottage on Sunday.