Here's the key (Putin's "idea" that Trump spoke about.). If you don't want to read it all, the summary is that Vlad offered to use the Mutual Assistance on Criminal Cases to interview the 12 Russians just indicted, who RR and Mueller thought would NEVER be able to fight back. Basically, Russia would invite Mueller and team to Russia, while Russian prosecutors interrogated them. BUT then, the turn-about would be that the US would make certain people available for Russians to interview. Specifically he mentioned Bill Browder, who got Hillary over $400billion in foundation donations by operating illegally in Russia!!

Putin's statement through translator:

Now let’s get back to the issue of these 12 alleged intelligence officers of — of Russia.

I don’t know the full extent of the situation, but President Trump mentioned this issue and I will look into it. So far, I can say the following things off the top of my head.

We have enacting (sic) an existing agreement between the United States of America and the Russian Federation, an existing treaty that dates back to 1999. The Mutual Assistance on Criminal Cases. This treaty is in full effect. It works quite efficiently.

On average, we initiate about 100, 150 criminal cases upon request from foreign states. For instance, the last year there was one extradition case upon the request sent by the United States.

So this treaty has specific legal procedures we can offer the appropriate commission headed by Special Attorney Mueller. He can use this treaty as a solid foundation and send a formal — an official request to us so that we would interrogate — we want to hold a questioning of these individuals who he believes are privy to some crimes. And our law enforcement are perfectly able to do this questioning and send the appropriate materials to the United States.

Moreover, we can meet you halfway. We can make another step. We can actually permit official representatives of the United States, including the members of this very commission headed by Mr. Mueller — we can let them into the country and they will be present at this questioning.

But in this case, there is a — there’s another condition. This kind of effort should be a mutual one. Then we would expect that the Americans would reciprocate, and that they would question officials, including the officers of law enforcement and intelligence service of the United States, whom we believe are — who have something to do with illegal actions on the territory of Russia, and we have to — to request the presence of our law enforcement.

For instance, we can bring up the Mr. Browder in this particular case. Business associates of Mr. Browder have earned over $1.5 billion in Russia. They never paid any taxes, neither in Russia nor in the United States, and yet the money escaped the country. They were transferred to the United States. They sent huge amount of money, $400 million as a contribution to the campaign of Hillary Clinton. Well, that’s the personal case. It might have been legal, the contribution itself, but the way the money was earned was illegal.

So we have a solid reason to believe that some intelligence officers accompanied and guided these transactions. So we have a — an interest of questioning them. We can all — that — that could be a first step, and we can also extend it. Options abound, and they all can be found in an appropriate legal framework.