(CNN) — President Donald Trump’s lawyer, Rudy Giuliani, said Monday that he’s not sure collusion with Russia would be considered a crime.

But legal experts have repeatedly said that anyone found collaborating with Russia on the 2016 election could be charged with other crimes, such as conspiracy — and special counsel Robert Mueller’s investigation is ongoing.

Asked about former Trump campaign chairman Paul Manafort’s upcoming trial, Giuliani told CNN “New Day” co-anchor Alisyn Camerota that Manafort “was not involved with intimate business relationships with Donald Trump.”

“Four months, they’re not going to be colluding with Russia, which I don’t even know if that’s a crime, colluding about Russians,” Giuliani, a former federal prosecutor, continued. “You start analyzing the crime — the hacking is the crime. … The President didn’t hack.”

The President has repeatedly denied that there was any collusion between his campaign and Moscow. But he has made a similar argument to that of Giuliani’s, telling The New York Times in December that “There is no collusion, and even if there was, it’s not a crime.”

At a CNN town hall in April, former FBI Director James Comey, whom Trump fired, said collusion “is not actually a thing that exists under the federal laws of the United States.”

Instead, Comey continued, the question is whether any Americans conspired with a foreign government to commit crimes against the US, which is a crime.

And speaking to CNN in May, Carrie Cordero, a CNN legal analyst and an adjunct senior fellow at the Center for a New American Security, said collusion isn’t a crime “in the literal sense” but that there could be related criminal violations in colluding, such as receiving foreign money in a political campaign or assisting with or being an accessory to computer hacking.

No evidence has publicly emerged that the Trump campaign has engaged in these activities, though Mueller’s investigation is ongoing.

Since Mueller’s investigation began in spring 2017, the probe has resulted in criminal charges against several Russian nationals, five Americans and one Dutch citizen and three corporate entities. One of those people has already been sentenced and served a month in prison, while three others pleaded guilty and await sentencing.

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