As details of the horrific beheading swept across the internet, members of the Islamic State posted a flood of sickening messages on Twitter.
The fanatics, who had travelled from Britain and across the world to fight in Iraq and Syria, mercilessly joked about the murder of the innocent American journalist.
If they were not laughing, they were telling of their own desires to commit atrocities of the same barbaric nature.
A British jihadist, Nasser Muthana, writing under the name Abul Muthanna, tweeted: ‘So America wants to protect Yazidis from genocide but can’t even protect their own citizens from getting decapitated.’
Fighting in Syria, a London-born woman, Khadijah Dare, used the name Muhajirah fi Sham to write: ‘UK must b shaking up haha. I wna b da 1st UK woman 2 kill a UK or US terrorist!’
A British woman in Syria, using the alias al-Britaniyya, wrote: ‘So the US want to bombard us with airstrikes in Iraq and not give a damn who’s killed but want to cry when a dusty journalist is killed.
‘By Allah we won’t forget our Muslim brothers and sisters who were killed by United States… the blood of a Muslim is not cheap.’
British jihadist Reyaad Khan, from Cardiff, writing under the name Abu Dujana, said: ‘A message from #IS to Obama. Withdraw or chaos will “be-heading” your way.’
A Canadian jihadist, using the name Abu Turaab al-Kanadi, said: ‘Can’t wait for the day #IS beheads the first American soldier #SoccerAnyone?’
Following the circulation of the murder footage, he added: ‘I guess it’s time to play soccer boys :)’ – a sick reference to the beheading of Mr Foley.
This was followed by: ‘Seeing these so called “Muslims” send condolences to James Foley’s family is disgusting. No dignity whatsoever…’
Abu Farris, another IS fighter, wrote: ‘The message the state sent to Obama is simple; don’t get involved in our war and we really are not joking. We’re ready like never before..’
Abu Muhammad wrote: ‘Obama statement in short: no negotiation,’ followed by ‘Ha, Obama just wrote the death sentence of the second guy.’
Extremists in the UK also exhibited a shocking lack of humanity.
Anjem Choudary wrote: ‘The presence of US forces in Muslim countries is a cause of instability there & a cause of insecurity back in the US. Hands off Muslim land!’