It's happened again.
http://www.cnn.com/2014/09/13/world/meast/isis-haines-family-message/
http://www.cnn.com/2014/09/13/world/meast/isis-haines-family-message/
The ISIS video post showing Haines' beheading called his execution "a message to the allies of America."
It is produced very similarly to the videos that showed the executions of American journalists James Foley and Steven Sotloff, the last of which included Haines and the threat that he'd be killed next.
The new video pictures a masked ISIS militant placing his hand on another captive, whom he identified as Alan Henning, a British citizen.