International investigators looking into the downing of Malaysia Airlines Flight 17 in 2014 have found "strong indications" that implicate Russian President Vladimir Putin.

Investigators said on Wednesday that it's highly likely that Putin approved the decision to provide Russian separatists with long-range anti-aircraft missiles that were used to shoot down the plane, a passenger jet that was carrying almost 300 people at the time.

Prosecutors noted that despite "strong indications" that Putin approved the decision, they did not have "concrete enough" evidence to prosecute. Two former Russian state security officers and a separatist leader in Ukraine were convicted of murder in the downing, but none were ever arrested or extradited. The Kremlin has denied that Russia was involved.

"There is concrete information that the request from the separatists is presented to the president, and that a positive decision is taken," investigators said, according to CNN. "It is unknown whether the request explicitly mentions a Buk system. A short time later, heavy air-defense systems were delivered, including the Buk that later shot down MH17."

"The purpose of this investigation was to find out the truth, and I think we have come further than we ever imagined in 2014," deputy chief public prosecutor Digna van Boetzelaer said in a statement, according to The Washington Post. "The findings we have uncovered about the Russian involvement up to the highest level can play an important role in proceedings where the liability of this state is at issue."

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