An anonymous Twitter user has been served with US court papers by Northcliffe Media in a bid to force them to reveal their identity.
In its nine-page civil cover sheet, seen by The Huffington Post UK and filed in San Francisco, Northcliffe claims the person behind @UnSteveDorkland hacked into company computers.
The case centres around a spoof Twitter account which parodies Northcliffe's chief executive Steve Auckland - and uses a profile picture of George Clooney.
The individual could also face a full jury trial in the US if Northcliffe, the regional newspaper division of the Daily Mail & General Trust, which also owns Metro, gets its own way.
Northcliffe's full complaint is for "computer fraud and abuse, computer data access and fraud, and defamation/libel per se".
The papers also allege the mystery tweeter has three accounts which are used to post "false and defamatory statements".
"At least some of the information made public on Twitter by the Defendant was not known publically, and on information and belief, the only way that such information could be obtained was by hacking into an account at the Plaintiff's business."
The papers, filed against the name John Doe (a name used when the Defendant is unknown) also state that "unless restrained the Defendant will continue to commit such acts... the Defandant has caused irreparable and incalcuable harm."
Via email, the person behind @UnSteveDorkland told The Huffington Post UK: "The court documents behind the subpoena are amazing - suggesting I have been indulging in hacking, surveillance of staff and am responsible for the poor trading performance of the company.
"They have basically thrown the book at me without any real evidence; I suspect because they thought I would not have the means or the will to fight them in a Californian court.
"I WILL be fighting the subpoena. I have a lawyer working for me in California and papers will be filed in time this week to fight it before the deadline."
The story first came to light last week when it was reported by the Guido Fawkes blog.
Previously the person behind the @UnSteveDorkland account has told The Guardian: "It was a parody, pure and simple.
Made a few people laugh, I hope. Pointed out some of the absurdities of corporate life."
Neither Northcliffe Media nor Steve Auckland were available for comment at the time of publishing.