Relatives of freelance journalist Steven Sotloff are aware of a new video purporting to show his beheading by Islamic State militants.
In a two-sentence statement today, family spokesman Barak Barfi said Mr Sotloff's family "knows of this horrific tragedy and is grieving privately".
The family has not been told whether the video is authentic, and Mr Barfi said the family does not plan to make any additional comments now.
I've been told at the Nato summit that the intelligence services know exactly who 'Jihadi John' is - or at least are 99.9% certain.
The British aid worker being held by Islamic State is David Haines, a 44-year-old father-of-two from Perth, Scotland.
In a video statement which claims to record his final words US hostage and journalist Steven Sotloff blames US foreign policy for his death.