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.
Earlier, the State Department said US intelligence officials were still trying to determine if the video was genuine.
Mr Sotloff had been held by the Islamic State since last year.