What we know about the terror attack in Russia and the ISIS group claiming responsibility

Russian President Putin has vowed to punish those responsible for the terror attack on a suburban Moscow concert hall that killed at least 133 people. In the capital, people are remembering the dead after one of the worst acts of terror in Russia in decades. Journalist Michael Weiss joins John Yang to discuss the Islamic State branch that claimed responsibility for the attack and Putin's response. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders