- The four ISIS videos have several similar elements
- In all, a black clad man with a British accent addresses Western leaders
- The Alan Henning video has a few differences
- It's not as long as the other videos and Henning speaks less
The videotaped, apparent beheading of a fourth Westerner by ISIS holds strong similarities to the prior three. In all four videos, the victims are kneeling in orange clothing on the sand and a black-clad man with a British accent speaks to Western leaders.
But the taped killing of British aid worker Alan Henning differs in some ways, most notably in being much shorter, at one minute and 11 seconds.
Henning speaks very briefly, for 10 seconds, and appears less composed than at least two of the others.
The camera has only one angle throughout, whereas there were multiple angles in the videotaped killings of American journalists James Foley and Steven Sotloff. Foley's video ran five minutes and Sotloff's two minutes and 47 seconds.
The latest tape, released Friday, opens with a short news clip on the British Parliament approving military strikes against ISIS from the Russian news agency Russia Today.
Then the recording goes to a slate that reads "Another Message to America and its Allies."
Henning speaks, apparently forced to read a script as the other three victims had.
A masked man dressed in black standing over Henning makes a reference to the third Westerner beheaded by ISIS, British aid worker David Haines. The killer says his message is for British Prime Minister David Cameron.
"The blood of David Haines was on your hands, Cameron. Alan Henning will also be slaughtered, but his blood is on the hands of the British Parliament," the knife-wielding killer says.
In all four videos, the man wears black garb covering everything almost but his eyes. He wears a leather strap with a pistol and waves a knife in his left hand. He speaks with a British accent.
"It sounds, and he looks very much, like the same executioner that we've seen in the two previous killings," CNN's Nic Robertson said in an interview when ISIS released the video of the third beheading. "That accent there is unmistakably British."
However, since the mask covers the man's mouth, it cannot be confirmed he's the one speaking.
It's also not certain the man actually kills the hostages because the video goes to black before the beheading occurs.
Last week, FBI Director James Comey said the United States believes it has identified the ISIS militant in the video showing Foley's killing. Comey did not publicly identify the man but FBI officials said they believe the same militant speaks in the videos showing Foley, Sotloff and Haines.