Jihadists holding US journalist James Foley wanted a $132m (£80m) ransom for his release, his employer has said.
GlobalPost CEO Philip Balboni said the Islamic State (IS) militants first demanded money last year.
Mr Foley was abducted in November 2012, and a video of his beheading was released by IS earlier this week.
In it, they threatened to kill another American if the US did not stop its air strikes against the group in northern Iraq.
US air strikes have continued near Mosul despite the warning.
The US has begun a formal criminal investigation into the Mr Foley's death, with Attorney General Eric Holder saying that the US has a "long memory and our reach is very wide".
In the UK, police and security services are trying to identify the jihadist who appeared in footage of Mr Foley's killing.
Unconfirmed reports suggest the man - who had an English accent - is from London or south-east England.