Washington’s envoy to Syria claims the group, which was once called the ‘Free Syrian Army’, committed ‘war crimes’ during Turkey’s offensive in northern Syria. Turkey has pledged to investigate the allegations. Relations between Washington and the militants in Syria have not always been that strained. Some were armed and promoted by America during their fight against the Syrian government. RT’s Caleb Maupin looks now at how groups, once fiercely backed by the US, have evolved into what they are now.