Clapper doesn't rule out ISIS involvement in downing of Russian plane

Clapper doesn't rule out ISIS involvement in downing of Russian plane:

Two days after the fatal plane crash over Egypt, the director of U.S. national intelligence on Monday said he wouldn't rule out the possibility that the Islamic State in Iraq and Syria (ISIS) could shoot down an airliner.

http://www.cbsnews.com/news/top-u-s-official-doesnt-rule-out-possibility-that-isis-shot-down-plane/