How about stolen Kuwaiti incubators, the lie that tricked America into the first invasion of Iraq? Or Saddam's nuclear weapons, the lie that tricked America into the second invasion of Iraq? The US government needs to invade Iraq for a third time, to keep Iraq's oil selling only for US dollars and as is the usual pattern, the news is flooded with spectacular stories unsupported by any proof as to why Americans should go along with this third invasion of Iraq. The video of "ISIS" stating they will fly the flag of Allah over the White House has already been exposed as a fraud.
To detect a lie, look for what should be there and isn't, and what is missing from this story is a REASON for ISIS to behead children, knowing that such an act will turn world opinion against them and open the door for a US military invasion. These are not stupid people. Many were armed and trained by the US to use against Syria's Assad. They understand that without popular support from the American people, the US cannot launch another war, especially in an election year. So, why would ISIS hand the US Government any propaganda weapon that would work against them? The answer is, they wouldn't do that.
Look at how many wars were started with lies and deceptions. America was tricked into World War 1 with the claim that Lusitania was not carrying weapons. That was proven a lie when divers entered the hold of the wreck in the 1980s and confirmed the presence of a military cargo, which made Lusitania a legitimate target of war. Or the claim that a Spanish mine sunk the USS Maine in Havana Harbor that led to the Spanish American War? The Captain of the USS Maine insisted that the ship had been destroyed by an onboard fire, but President McKinley, aided by the Hearst newspapers, sold the lie of a Spanish mine to the American people. A later investigation led by Admiral Hyman G. Rickover, the father of America's nuclear Navy, concluded there had been no mine and the Captain of the USS Maine had been telling the truth. Lyndon Johnson escalated the war in Vietnam by claiming the USS Maddox was attacked by Torpedoes in the Gulf of Tonkin, which turned out never top have existed.
Every war in history is started by some leader lying their population into thinking the war is the only possible course of action, and as I mentioned at the top, the two previous invasions of Iraq were launched with hoaxes about stolen incubators and non-existent nuclear weapons.
This is just more of the same USDA Choice Bovine Excrement!