Although hacking is very difficult to fully track, it adds up that Putin would be responsible. We all know how Putin likes to go about his business, and that cyber is the new form of non-physical attack. Being one of Americans keep enemies he has to be put squarely in the frame.
The CIA, FBI and a whole host of American intelligence agencies have found proof that Russia is the source of the hacking of the DNC computer system. Sources say that the hacking came from the "highest levels" in Russia. That means the hacking come from the president of Russia. Putin is the president of Russia. Therefore, he knew about the hacking of the DNC computer system and is responsible for it.
It is not completely clear that Putin or any other foreign intelligence agency was responsible for the hack of the DNC computer system. The individual or group responsible for the hacking apparently had a grudge against the Clinton campaign. There has been speculation that an American intelligence officer might have hacked the DNC and leaked the emails.
If Russia state agents are proven to have been the actors in the Democratic National Congress email hacks, then it will be fair to say that President Putin approved of the action. Nothing so serious could have been undertaken without the consent of the President in terms of the Russian Federation. However, the CIA and the FBI have not definitively concluded that Russia was the guilty party yet, so it is too early to say.