The head of counterintelligence for Ukraine’s state security service, Vitaly Nayda, said a Russian official was behind the attack on Malaysia Airlines Flight MH17. Nayda told CNN Tuesday that the official "pushed the button."

An unreleased audio recording between two officers is reportedly among the evidence Ukraine has that points to Russian involvement in the downing of MH17. "We know for sure that several minutes before the missile was launched, there was a report" to a Russian officer that the plane was coming, Nayda told CNN. Ukraine recorded several conversations between Russian officers, he added.

Ukraine released audio Thursday of a conversation between Russian intelligence officials while Sunday the Security Service of Ukraine released audio of pro-Russian separatists planning to conceal the MH17 black boxes. Nayda said the separatists would have known it was a "big civilian plane."

Russia has denied any involvement in the downing of MH17 while separatists have denied they have the capability to shoot down a plane. Separatists handed over the MH17 black boxes to Malaysian officials on Monday. The separatists also agreed to deliver the recovered bodies of 282 passengers to the Netherlands, and Dutch Prime Minister Mark Rutte said the remains will arrive on Wednesday in Eindhoven.