The threats follow the club's decision to consider moving to a new stadium.

The police were called in to investigate the threats which target Ridsdale and his two daughters, aged three and five.

Ridsdale said: "I feel threats being made against my children go beyond what anyone would expect from individuals calling themselves Leeds United supporters."

The Sunday People newspaper reported that, as part of an extensive investigation, West Yorkshire police have taken away evidence for DNA testing and handwriting analysis.

Leeds moved closer to being able to reveal the preferred site of a possible new ground earlier this month following meetings with Leeds City Council.

The club are looking at a possible move to new site near the A1-M1 link road at Garforth.

But it have stated no decision to move will be made before the club have consulted the fans and have the backing of the council.

Ridsdale said then: "We have promised all along that we would consult with our fans every step of the way.

"We hope to be able to show them where we would build a new stadium if the decision was made to leave Elland Road.

Ray Fell, chairman of the Leeds United Supporters' Club, came out in support of Ridsdale.

He said: "In Peter Ridsdale, we have a statesman and a fans' chairman, and to rock the boat in this way is inexplicable and unbelievable.

"These people are outside Leeds, but they're not real fans.

"I can only appeal to the genuine fans that, if they have any information to help in solving this problem, that they come forward and do so."

On the proposed move, Fell added: "It's something that affects fans and wherever there is a gathering of fans, there are going to be differences of opinion.

"That's the nature of the game, but the important thing is that the club does what is best for Leeds United, not for any individual.

"It will be a board decision and a club decision, but one in which the fans are involved.

"I understand letters are going out and I would say that fans will abide by what's best for the club. Wherever Leeds go, the true fans will be there with them."