Kim Dotcom's extradition might "never occur", says a music company challenging delays to a copyright legal case.
Microhits has asked the United States courts to stop delaying its case against Megaupload until the extradition issue is resolved - because it might never happen.
New papers filed with the US district court in Virginia say the extradition is "a mere possible future event but indeed an event which may in fact never occur".
Microhits filed its lawsuit against Megaupload after the FBI-inspired raid which saw Mr Dotcom and three business partners arrested on criminal copyright charges.
The FBI criminal case sent shockwaves through the filesharing world with the Megaupload websites taken over by the US and shut down. The Microhits case followed a few months later with a more usual civil court bid over copyright infringement.
Microhits - which lists Christina Aguilera, Aretha Franklin, Marvin Gaye and Dr Dre on its music catalogue - had its initial bid put on hold for 180 days to allow the United States Government's case against Megaupload to go ahead.
It also faced criticism from Megaupload's lawyers who argued its lawsuit was a cut-and-paste of the FBI's indictment.
Microhits lawyers have now argued the company should be allowed to pursue its case against Megaupload because it has already had more success in its civil case than the US Government in its criminal case. They pointed to the serving of a summons against Megaupload, Mr Dotcom and his colleague Mathias Ortmann - the FBI has yet to serve legal papers on all those it wants to prosecute.
The papers filed in the US said "there is no end in sight to the current criminal extradition proceedings" - a claim which was made before the latest delays in the case saw the hearing postponed until August 2013.
Microhits also pointed to the potential loss of any damages. They said Mr Dotcom had posted messages on his Twitter account in which he wrote about his new Mega business. In the posts, Microhits said he had "openly avowed to move their assets and operations out of reach of the United States".
Mr Dotcom's lawyers dismissed the claim, saying another delay of six months would allow progress against the FBI case. They also dismissed concern about the launch of Mega, saying "nothing has happened yet". They said the US Government had seized the assets and were "doling out limited amounts for living expenses and foreign counsel".
"Defendants' assets are still sequestered and no amount of tweets and blog-posts will 'un-freeze them' - that requires a court order."
Mr Dotcom's team said facing the civil action would be difficult because of no access to seized funds, seizure of books and records and no access to the former Megaupload servers. The FBI has copied parts of the servers and wanted to delete the rest.
His lawyers said Microhits and Megaupload wanted access to the information on the servers as a "critical source of proof".