The ISIS spy who betrayed al-Baghdadi was an insider motivated by revenge

NORTHERN SYRIA — The Islamic State militant group's leader Abu Bakr al-Baghdadi was betrayed by a member of his inner circle who helped lead American troops to his compound in northern Syria.

The commander of the Kurdish-led Syrian Democratic Forces, Gen. Mazloum Abdi, gave NBC News a detailed account of how he spent months running a spy inside ISIS who followed al-Baghdadi as he moved from one safe house to another, until he was finally trapped in a tunnel beneath one of them.

Abdi did not identify the source, but...