It has been revealed that threats, allegedly sent to former Luton boss Nathan Jones, are being investigated by the police.
Jones, 45, left the League One club to join Stoke last month.
Luton were second in the table when the Welshman left and his departure was unpopular with some supporters.
Hertfordshire Police revealed the force are investigating reports a man in his forties received malicious communications.
Jones was appointed Luton manager in January 2016 and guided the club to promotion last season. He admitted it was a “real wrench” to leave Kenilworth Road.
“The amount of times I’ve cried from text messages from players… it makes me emotional because I was married to the club,” he said.
“It’s a calculated gamble but it’s the right step for me and the club. I think I’ve left them in a wonderful position.
“It really wasn’t (an easy decision). I had a really good place at Luton, it was a wonderful club. We were in a wonderful place.
“When it happens you just have to put things aside and think professionally. It was a real wrench, we built something special at Luton and it would have taken something special.
“I had the opportunity to leave (before) and I never did, when this came up it was too good to turn down.”
Luton are top of League One under caretaker manager Mick Harford, while Stoke are 15th in the Championship after four defeats in their last five league games.