ISIS has beheaded four Westerners on video – two Americans and two Brits. In each case the victims appear to have been either leftists or individuals who were sympathetic to Syria’s rebels. The latest victim is Alan Henning, a Brit who went so far as having a tattoo on his arm that expressed solidarity with the opposition:

Henning’s death follows that of Haines, a British aid worker, as well as two American journalists, James Foley and Steven Sotloff, who were all killed separately in a similar, brutal fashion.

Following the latest video’s release, Cameron took to Twitter, saying the “brutal murder of Alan Henning by ISIL [ISIS] shows just how barbaric these terrorists are.”

In a statement released today, President Obama said the U.S. “strongly condemns” Henning’s murder and said his was a “great loss for [the Syrian people], for his family and the people of the United Kingdom.”

“Standing together with our U.K. friends and allies, we will work to bring the perpetrators of Alan’s murder – as well as the murders of Jim Foley, Steven Sotloff and David Haines – to justice,” Obama said.

The British Parliament voted late last week to join coalition airstrikes on ISIS targets in Iraq after Cameron made a passionate plea to lawmakers.

“This is about psychopathic terrorists that are trying to kill us and we do have to realize that, whether we like it or not, they have already declared war on us,” Cameron said then. “There isn’t a ‘walk on by’ option. There isn’t an option of just hoping this will go away.”

Like other victims before him, Henning clearly exhibited poor judgment. Here is a news report that explains how he was kidnapped:

h/t BNI