Premier League referee Mark Halsey has made a complaint to Greater Manchester Police after being the subject of two abusive tweets on Sunday.
The insulting messages about Halsey were posted on the social networking site Twitter, referencing his battle with throat cancer in 2009, after taking charge of Liverpool's contentious 2-1 defeat against Manchester United.
And the 51-year-old has asked the police to investigate the matter, a Professional Game Match Officials Limited (PGMOL) spokesman confirmed to Press Association Sport.
The abusive tweets come just days after the Director of Public Prosecutions said new guidelines for prosecutors on social media cases will be issued in the wake of a number of growing complaints.
Last week a Welsh Premier League footballer who posted an abusive message about Olympic diver Tom Daley was not charged because the message was "not so grossly offensive that criminal charges need to be brought", Keir Starmer said.
But Starmer, the most senior prosecutor in England and Wales, added: "The time has come for an informed debate about the boundaries of free speech in an age of social media."
Halsey made three controversial decisions on Sunday, all of which went in favour of Manchester United, sending off Liverpool midfielder Jonjo Shelvey before awarding United a penalty, which was scored by Robin van Persie, then failing to give Liverpool one when Luis Suarez appeared to be fouled.
Two tweets were sent out by disgruntled Liverpool supporters following the game, both of which were met with outrage from other Twitter users.
One post, from an account named @johnwareing1, read: "I hope Mark Halsey gets cancer again and dies" while another from @lfcjohn259 read: "Mark Halsey should've died of cancer."
The post from @lfcjohn259 was deleted and the @johnwareing1 account was removed completely but the national secretary of Prospect, Alan Leighton, expressed his union's disgust regarding the tweets in a statement to Press Association Sport.
His statement read: "Prospect wholeheartedly condemns the unacceptable abuse aimed at Mark Halsey on Twitter. The comments made by a very small minority will be seen as beneath contempt by all decent people.
"The main concern now is for Mark and his family, who are receiving the support of his employer, PGMOL. Prospect will also provide any assistance as required."
Halsey returned to refereeing in March 2010 following his battle against his illness and is due to officiate the Capital One Cup third-round meeting between Southampton and Sheffield Wednesday on Tuesday night as originally planned.
The abusive Twitter users were also condemned by PGMO, which provides referees to the Premier League, offering support to Halsey if and when it is required.
Their statement read: "PGMO abhors any abuse of match officials whether that is in stadia or outside of it.
Our main concern is towards Mark and his family, and as with all match officials, there is a backroom team who are there for them.
"This includes a sports psychologist, who has worked extensively with the Select Group including Mark over the past few years. Mark has already benefited from the support of all of his Select Group colleagues and they will continue to back him this week.
"None of the Select Group match officials are on social media."
Halsey showed a red card to Shelvey for a challenge on Jonny Evans but both managers had different views on the decision with Liverpool boss Brendan Rodgers also questioning the award of United's penalty.
United manager Sir Alex Ferguson said of the decision: "I thought it was a clear red card.
"I don't think he went for the ball - Jonny Evans went for the ball and got the ball - and the boy's gone in really dangerously and I don't think there's any other decision the referee could have given."
But Rodgers was adamant his side had been hard done by.
"Jonjo Shelvey, if he gets sent off, then Jonny Evans has to go as well. I think both players' feet are off the floor," he said.
"I'm sure it's never a penalty, and then obviously Luis Suarez goes up the other end and gets a toe to the ball and the defender doesn't touch the ball, and he goes down and it looks a penalty. That was out of our control."
Shelvey himself felt he should not have been shown a red card and was also seen to be remonstrating with Ferguson as he left the pitch.
The England Under-21 international used Twitter to apologise to the fans and suggest Ferguson played a hand in his dismissal.
He said: "I apologise to the fans for getting sent off but no way was I pulling out of that tackle in a game of that importance. I'm sorry.
"I have also apologized to Sir Alex, just where I come from people don't grass people up to get someone sent off."
