"A buildup of extraordinary circumstantial evidence ... it's powerful here," said Secretary of State John Kerry, a former prosecutor, and it holds Russian-supported rebels in eastern Ukraine responsible for shooting down Malaysia Airlines Flight 17, with the Kremlin complicit in the deaths of nearly 300 passengers and crew members. "This is the moment of truth for Russia," said Kerry, leveling some of Washington's harshest criticism of Moscow since the crisis in Ukraine began.